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+publicationDate,title,abstract,id
+2013-02-18,Comparative Measurements of Inverse Spin Hall and Magnetoresistance in YIG|Pt and YIG|Ta,"We report on a comparative study of spin Hall related effects and
+magnetoresistance in YIG|Pt and YIG|Ta bilayers. These combined measurements
+allow to estimate the characteristic transport parameters of both Pt and Ta
+layers juxtaposed to YIG: the spin mixing conductance $G_{\uparrow \downarrow}$
+at the YIG$|$normal metal interface, the spin Hall angle $\Theta_{SH}$, and the
+spin diffusion length $\lambda_{sd}$ in the normal metal. The inverse spin Hall
+voltages generated in Pt and Ta by the pure spin current pumped from YIG
+excited at resonance confirm the opposite signs of spin Hall angles in these
+two materials. Moreover, from the dependence of the inverse spin Hall voltage
+on the Ta thickness, we extract the spin diffusion length in Ta, found to be
+$\lambda_{sd}^\text{Ta}=1.8\pm0.7$ nm. Both the YIG|Pt and YIG|Ta systems
+display a similar variation of resistance upon magnetic field orientation,
+which can be explained in the recently developed framework of spin Hall
+magnetoresistance.",1302.4416v1
+2023-12-17,Cryogenic hybrid magnonic circuits based on spalled YIG thin films,"Yttrium iron garnet (YIG) magnonics has sparked extensive research interests
+toward harnessing magnons (quasiparticles of collective spin excitation) for
+signal processing. In particular, YIG magnonics-based hybrid systems exhibit
+great potentials for quantum information science because of their wide
+frequency tunability and excellent compatibility with other platforms. However,
+the broad application and scalability of thin-film YIG devices in the quantum
+regime has been severely limited due to the substantial microwave loss in the
+host substrate for YIG, gadolinium gallium garnet (GGG), at cryogenic
+temperatures. In this study, we demonstrate that substrate-free YIG thin films
+can be obtained by introducing the controlled spalling and layer transfer
+technology to YIG/GGG samples. Our approach is validated by measuring a hybrid
+device consisting of a superconducting resonator and a spalled YIG film, which
+gives a strong coupling feature indicating the good coherence of our system.
+This advancement paves the way for enhanced on-chip integration and the
+scalability of YIG-based quantum devices.",2312.10660v2
+2019-01-08,Fabrication of yttrium-iron-garnet/Pt multilayers for the longitudinal spin Seebeck effect,"For longitudinal spin Seebeck effect (LSSE) devices, a multilayer structure
+comprising ferromagnetic and nonmagnetic layers is expected to improve their
+thermoelectric power. In this study, we developed the fabrication method for
+alternately stacked yttrium-iron-garnet (YIG)/Pt multilayer films on a
+gadolinium gallium garnet (GGG) (110) substrate, GGG/[YIG(49 nm)/Pt(4 nm)]$_n$
+($n =$ 1 - 5) based on room-temperature sputtering and $ex$-$situ$
+post-annealing method and we evaluated their structural and LSSE properties.
+The fabricated [YIG/Pt]$_n$ samples show flat YIG/Pt interfaces and almost
+identical saturation magnetization $M_{\rm s}$, although they contain
+polycrystalline YIG layers on Pt layers as well as single-crystalline YIG
+layers on GGG. In the samples, we observed clear LSSE signals and found that
+the LSSE thermoelectric power factor (PF) increases monotonically with
+increasing $n$; the PF of the [YIG/Pt]$_5$ sample is enhanced by a factor of
+$\sim 28$ compared to that of [YIG/Pt]$_1$. This work may provide a guideline
+for developing future multilayerbased LSSE devices.",1901.02129v1
+2013-01-25,Intrinsic Spin Seebeck Effect in Au/YIG,"The acute magnetic proximity effects in Pt/YIG compromise the suitability of
+Pt as a spin current detector. We show that Au/YIG, with no anomalous Hall
+effect and a negligible magnetoresistance, allows the measurements of the
+intrinsic spin Seebeck effect with a magnitude much smaller than that in
+Pt/YIG. The experiment results are consistent with the spin-polarized
+density-functional calculations for Pt with a sizable and Au with a negligible
+magnetic moment near the interface with YIG.",1301.6164v1
+2014-10-05,Planar Hall effect in Y3Fe5O12(YIG)/IrMn films,"The planar Hall effect of IrMn on an yttrium iron garnet (YIG = Y3Fe5O12) was
+measured in the magnetic field rotating in the film plane. The magnetic field
+angle dependence of planar Hall resistance (PHR) has been observed in YIG/IrMn
+bilayer at different temperatures, while the GGG/IrMn (GGG= Gd3Ga5O12) shows
+constant PHR for different magnetic field angles at both 10 K and 300 K. This
+provides evidence that IrMn has interfacial spins which can be led by FM in
+YIG/IrMn structure. A hysteresis can be observed in PHR-magnetic field angle
+loop of YIG/IrMn films at 10 K, indicating the irreversible switching of IrMn
+interfacial spins at low temperature.",1410.1112v1
+2016-11-25,Electrical Detection of Spin Backflow from an Antiferromagnetic Insulator/Y3Fe5O12 Interface,"Spin Hall magnetoresistance (SMR) has been observed in Pt/NiO/Y3Fe5O12 (YIG)
+heterostructures with characteristics very different from those in Pt/YIG. We
+show that the SMR in Pt/NiO/YIG strongly correlates with spin conductance, both
+sharing very strong temperature dependence due to antiferromagnetic magnons and
+spin fluctuation. This phenomenon indicates that spin current generated by spin
+Hall effect in the Pt transmits through the insulating NiO and is reflected
+from the NiO/YIG interface. Inverted SMR has been observed below a temperature
+which increases with the NiO thickness, suggesting spin-flip reflection from
+the antiferromagnetic NiO exchange coupled with the YIG.",1611.08593v1
+2017-05-05,Thermographic measurements of the spin Peltier effect in metal/yttrium-iron-garnet junction systems,"The spin Peltier effect (SPE), heat-current generation due to spin-current
+injection, in various metal (Pt, W, and Au single layers and Pt/Cu
+bilayer)/ferrimagnetic insulator (yttrium iron garnet: YIG) junction systems
+has been investigated by means of a lock-in thermography (LIT) method. The SPE
+is excited by a spin current across the metal/YIG interface, which is generated
+by applying a charge current to the metallic layer via the spin Hall effect.
+The LIT method enables the thermal imaging of the SPE free from the
+Joule-heating contribution. Importantly, we observed spin-current-induced
+temperature modulation not only in the Pt/YIG and W/YIG systems but also in the
+Au/YIG and Pt/Cu/YIG systems, excluding the possible contamination by anomalous
+Ettingshausen effects due to proximity-induced ferromagnetism near the
+metal/YIG interface. As demonstrated in our previous study, the SPE signals are
+confined only in the vicinity of the metal/YIG interface; we buttress this
+conclusion by reducing a spatial blur due to thermal diffusion in an infrared
+emission layer on the sample surface used for the LIT measurements. We also
+found that the YIG-thickness dependence of the SPE is similar to that of the
+spin Seebeck effect measured in the same Pt/YIG sample, implying the reciprocal
+relation between them.",1705.02094v1
+2017-12-21,Exchange-torque-induced excitation of perpendicular standing spin waves in nanometer-thick YIG films,"Spin waves in ferrimagnetic yttrium iron garnet (YIG) films with ultralow
+magnetic damping are relevant for magnon-based spintronics and low-power
+wave-like computing. The excitation frequency of spin waves in YIG is rather
+low in weak external magnetic fields because of its small saturation
+magnetization, which limits the potential of YIG films for high-frequency
+applications. Here, we demonstrate how exchange-coupling to a CoFeB film
+enables efficient excitation of high-frequency perpendicular standing spin
+waves (PSSWs) in nanometer-thick (80 nm and 295 nm) YIG films using uniform
+microwave magnetic fields. In the 295-nm-thick YIG film, we measure intense
+PSSW modes up to 10th order. Strong hybridization between the PSSW modes and
+the ferromagnetic resonance mode of CoFeB leads to characteristic anti-crossing
+behavior in broadband spin-wave spectra. A dynamic exchange torque at the
+YIG/CoFeB interface explains the excitation of PSSWs. The localized torque
+originates from exchange coupling between two dissimilar magnetization
+precessions in the YIG and CoFeB layers. As a consequence, spin waves are
+emitted from the YIG/CoFeB interface and PSSWs form when their wave vector
+matches the perpendicular confinement condition. PSSWs are not excited when the
+exchange coupling between YIG and CoFeB is suppressed by a Ta spacer layer.
+Micromagnetic simulations confirm the exchange-torque mechanism.",1712.08204v1
+2013-04-08,YIG thickness and frequency dependence of the spin-charge current conversion in YIG/Pt systems,"We report the frequency dependence of the spin current emission in a hybrid
+ferrimagnetic insulator/normal metal system as function of the insulating layer
+thickness. The system is based on a yttrium iron garnet (YIG) film [0.2, 1, and
+3 \mu m] grown by liquid-phase-epitaxy coupled with a spin current detector of
+platinum [6 nm]. A strong YIG thickness dependence of the efficiency of the
+spin pumping has been observed. The highest conversion factor \Delta V/P_{abs}
+has been demonstrated for the thinner YIG (1.79 and 0.55 mV/mW^{-1} at 2.5 and
+10 GHz, respectively) which presents an interest for the realisation of
+YIG-based devices. A strong YIG thickness dependence of the efficiency of the
+spin pumping has been also observed and we demonstrate the threshold frequency
+dependence of the three-magnon splitting process.",1304.2190v1
+2016-04-28,Platinum/Yttrium Iron Garnet Inverted Structures for Spin Current Transport,"30-80 nm thick yttrium iron garnet (YIG) films are grown by pulsed laser
+deposition on a 5 nm thick sputtered Pt atop gadolinium gallium garnet
+substrate (GGG) (110). Upon post-growth rapid thermal annealing, single crystal
+YIG(110) emerges as if it were epitaxially grown on GGG(110) despite the
+presence of the intermediate Pt film. The YIG surface shows atomic steps with
+the root-mean-square roughness of 0.12 nm on flat terraces. Both Pt/YIG and
+GGG/Pt interfaces are atomically sharp. The resulting YIG(110) films show clear
+in-plane uniaxial magnetic anisotropy with a well-defined easy axis along <001>
+and a peak-to-peak ferromagnetic resonance linewidth of 7.5 Oe at 9.32 GHz,
+similar to YIG epitaxilly grown on GGG. Both spin Hall magnetoresistance and
+longitudinal spin Seebeck effects in the inverted bilayers indicate excellent
+Pt/YIG interface quality.",1604.08465v1
+2018-10-17,Perpendicularly magnetized YIG films with small Gilbert damping constant and anomalous spin transport properties,"The Y3Fe5O12 (YIG) films with perpendicular magnetic anisotropy (PMA) have
+recently attracted a great deal of attention for spintronics applications.
+Here, we report the induced PMA in the ultrathin YIG films grown on
+(Gd2.6Ca0.4)(Ga4.1Mg0.25Zr0.65)O12 (SGGG) substrates by epitaxial strain
+without preprocessing. Reciprocal space mapping shows that the films are
+lattice-matched to the substrates without strain relaxation. Through
+ferromagnetic resonance and polarized neutron reflectometry measurements, we
+find that these YIG films have ultra-low Gilbert damping constant with a
+magnetic dead layer as thin as about 0.3 nm at the YIG/SGGG interfaces.
+Moreover, the transport behavior of the Pt/YIG/SGGG films reveals an
+enhancement of spin mixing conductance and a large non-monotonic magnetic field
+dependence of anomalous Hall effect as compared with the Pt/YIG/Gd3Ga5O12 (GGG)
+films. The non-monotonic anomalous Hall signal is extracted in the temperature
+range from 150 to 350 K, which has been ascribed to the possible non-collinear
+magnetic order at the Pt/YIG interface induced by uniaxial strain.",1810.07384v2
+2023-06-24,Magnon confinement in an all-on-chip YIG cavity resonator using hybrid YIG/Py magnon barriers,"Confining magnons in cavities can introduce new functionalities to magnonic
+devices, enabling future magnonic structures to emulate established photonic
+and electronic components. As a proof-of-concept, we report magnon confinement
+in a lithographically defined all-on-chip YIG cavity created between two
+YIG/Permalloy bilayers. We take advantage of the modified magnetic properties
+of covered/uncovered YIG film to define on-chip distinct regions with
+boundaries capable of confining magnons. We confirm this by measuring multiple
+spin pumping voltage peaks in a 400 nm wide platinum strip placed along the
+center of the cavity. These peaks coincide with multiple spin-wave resonance
+modes calculated for a YIG slab with the corresponding geometry. The
+fabrication of micrometer-sized YIG cavities following this technique
+represents a new approach to control coherent magnons, while the spin pumping
+voltage in a nanometer-sized Pt strip demonstrates to be a non-invasive local
+detector of the magnon resonance intensity.",2306.14029v2
+2023-09-21,Single-crystalline YIG nanoflakes with uniaxial in-plane anisotropy and diverse crystallographic orientations,"We study Y3Fe5O12 (YIG) nanoflakes that we produce via mechanical cleaving
+and exfoliation of YIG single crystals. By characterizing their structural and
+magnetic properties, we find that these YIG nanoflakes have surfaces oriented
+along unusual crystallographic axes and uniaxial in-plane magnetic anisotropy
+due to their shape, both of which are not commonly available in YIG thin films.
+These physical properties, combined with the possibility of picking up the YIG
+nanoflakes and stacking them onto nanoflakes of other van der Waals materials
+or pre-patterned electrodes or waveguides, open unexplored possibilities for
+magnonics and for the realization of novel YIG-based heterostructures and
+devices.",2309.12477v1
+2018-11-29,"High Saturation Magnetization, Low Coercivity and Fine YIG Nanoparticles Prepared by Modifying Co-Precipitation Method","Nanoparticles with their specific properties newly have drawn a great deal of
+attention of researchers [1-3]Yttrium iron Garnet magnetic nanoparticles
+(YIG-NPs) are promising materials with novel applications in microwave,
+spintronics, magnonics, and magneto-optical devices. However, achieving stable
+and remarkable magnetic YIG-NPs has been remaining as a great challenge. In
+this paper, synthesized YIG-NPs by modifying co-precipitation (MCP) method is
+reported. Structural and magnetic properties of final products are compared to
+those of the materials prepared by citrate-nitrate (CN) method. Smaller
+crystals and particle size have been found by MCP method comparing to that of
+synthesized by CN method. Using a relatively low annealing temperatures for
+both sets of samples (~700 {\deg}C), the final YIG samples prepared by MCP
+method show more structural purity than those made by CN method. Higher
+saturation magnetization (Ms) and lower coercivity (Hc) are observed in MCP YIG
+sample (23.23 emu/g 36 and 30.1 Oe) than the CN prepared YIG sample (16.43
+emu/g and 44.95 Oe). The Curie temperature is measured to be 569 {\deg}C for
+the MCP YIG sample determined from set of Ms measurement at different
+temperatures ranging from 80-600 K. These findings lead to significant
+improvement in quality of synthesized (synthetic methods) of YIG-NPs.",1811.12511v1
+2018-11-29,Structural and Magnetic Study of Metallo-Organic YIG Powder Using 2-ethylhexanoate Carboxylate Based Precursors,"The crystallization and magnetic behavior of yttrium iron garnet (YIG)
+prepared by metallo-organic decomposition (MOD) method are discussed. The
+chemistry and physics related to synthesis of iron and yttrium carboxylates
+based on 2-ethylhexanoic acid (2EHA) are studied, since no literature was found
+which elucidates synthesis of metallo-organic precursor of YIG in spite of the
+literatures of doped YIG samples such as Bi-YIG. Typically, the metal
+carboxylates used in preparation of ceramic oxide materials are
+2-ethylhexanoate (2EH) solvents. Herein, the synthesis, thermal behavior and
+solubility of yttrium and iron 2EH used in synthesis of YIG powder by MOD are
+reported. The crystallization and magnetic parameters, including saturation
+magnetization and coercivity of these samples, smoothly change as a function of
+the annealing temperature. It is observed that high sintering temperature of
+1300 to 1400 {\deg}C promotes the diffraction peaks of YIG, therefore, we can
+conclude that the formation of YIG in MOD method increases the crystallization
+temperature. The maximum value of saturation magnetization and minimum value of
+coercivity and remanence are observed for the sample sintered at 1200{\deg}C
+which are 13.7 emu/g, 10.38 Oe and 1.5 emu/g, respectively. This study cites
+the drawbacks in chemical synthesis of metallo-organic based YIG production.",1811.12514v1
+2013-09-09,Induced magneto-transport properties at palladium/yttrium iron garnet interface,"As a thin layer of palladium (Pd) is directly deposited on an yttrium iron
+garnet or YIG (Y3Fe5O12) magnetic insulator film, Pd develops both low- and
+high-field magneto-transport effects that are absent in standalone Pd or thick
+Pd on YIG. While the low-field magnetoresistance peak of Pd tracks the coercive
+field of the YIG film, the much larger high-field magnetoresistance and the
+Hall effect do not show any obvious relationship with the bulk YIG
+magnetization. The distinct high-field magneto-transport effects in Pd are
+shown to be caused by interfacial local moments in Pd.",1309.2213v1
+2015-09-14,Spin Transport in Antiferromagnetic Insulators Mediated by Magnetic Correlations,"We report a systematic study of spin transport in antiferromagnetic (AF)
+insulators having a wide range of ordering temperatures. Spin current is
+dynamically injected from Y3Fe5O12 (YIG) into various AF insulators in
+Pt/insulator/YIG trilayers. Robust, long-distance spin transport in the AF
+insulators is observed, which shows strong correlation with the AF ordering
+temperatures. We find a striking linear relationship between the spin decay
+length in the AFs and the damping enhancement in YIG, suggesting the critical
+role of magnetic correlations in the AF insulators as well as at the AF/YIG
+interfaces for spin transport in magnetic insulators.",1509.04336v1
+2016-03-11,Investigation of anomalous-Hall and spin-Hall effects of antiferromagnetic IrMn sandwiched by Pt and YIG layers,"We report an investigation of temperature and IrMn layered thickness
+dependence of anomalous-Hall resistance (AHR), anisotropic magnetoresistance
+(AMR), and magnetization on Pt/Ir20Mn80/Y3Fe5O12 (Pt/IrMn/YIG)
+heterostructures. The magnitude of AHR is dramatically enhanced compared with
+Pt/YIG bilayers. The enhancement is much more profound at higher temperatures
+and peaks at the IrMn thickness of 3 nm. The observed spin-Hall
+magnetoresistance (SMR) in the temperature range of 10-300 K indicates that the
+spin current generated in the Pt layer can penetrate the entire thickness of
+the IrMn layer to interact with the YIG layer. The lack of conventional
+anisotropic magnetoresistance (CAMR) implies that the insertion of the IrMn
+layer between Pt and YIG efficiently suppresses the magnetic proximity effect
+(MPE) on induced Pt moments by YIG. Our results suggest that the dual roles of
+the InMn insertion in Pt/IrMn/YIG heterostructures are to block the MPE and to
+transport the spin current between Pt and YIG layers. We discuss possible
+mechanisms for the enhanced AHR.",1603.03578v2
+2020-11-15,A tunable magneto-acoustic oscillator with low phase noise,"A frequency-tunable low phase noise magneto-acoustic resonator is developed
+on the base of a parallel-plate straight-edge bilayer consisting of a
+yttrium-iron garnet (YIG) layer grown on a substrate of a gallium-gadolinium
+garnet(GGG). When a YIG/GGG sample forms an ideal parallel plate, it supports a
+series of high-quality-factor acoustic modes standing along the plate
+thickness. Due to the magnetostriction of the YIG layer the ferromagnetic
+resonance (FMR) mode of the YIG layer can strongly interact with the acoustic
+thickness modes of the YIG/GGG structure, when the modes' frequencies match. A
+particular acoustic thickness mode used for the resonance excitations of the
+hybrid magneto-acoustic oscillations in a YIG/GGG bilayer is chosen by the YIG
+layer FMR frequency, which can be tuned by the variation of the external bias
+magnetic field. A composite magneto-acoustic oscillator, which includes an
+FMR-based resonance pre-selector, is developed to guarantee satisfaction of the
+Barkhausen criteria for a single-acoustic-mode oscillation regime. The
+developed low phase noise composite magneto-acoustic oscillator can be tuned
+from 0.84 GHz to 1 GHz with an increment of about 4.8 MHz (frequency distance
+between the adjacent acoustic thickness modes in a YIG/GGG parallel plate), and
+demonstrates the phase noise of -116 dBc/Hz at the offset frequency of 10 kHz.",2011.07648v1
+2021-09-13,Control of magnetization dynamics by substrate orientation in YIG thin films,"Yttrium Iron Garnet (YIG) and bismuth (Bi) substituted YIG (Bi0.1Y2.9Fe5O12,
+BYG) films are grown in-situ on single crystalline Gadolinium Gallium Garnet
+(GGG) substrates [with (100) and (111) orientations] using pulsed laser
+deposition (PLD) technique. As the orientation of the Bi-YIG film changes from
+(100) to (111), the lattice constant is enhanced from 12.384 {\AA} to 12.401
+{\AA} due to orientation dependent distribution of Bi3+ ions at dodecahedral
+sites in the lattice cell. Atomic force microscopy (AFM) images show smooth
+film surfaces with roughness 0.308 nm in Bi-YIG (111). The change in substrate
+orientation leads to the modification of Gilbert damping which, in turn, gives
+rise to the enhancement of ferromagnetic resonance (FMR) line width. The best
+values of Gilbert damping are found to be (0.54)*10-4, for YIG (100) and
+(6.27)*10-4, for Bi-YIG (111) oriented films. Angle variation measurements of
+the Hr are also performed, that shows a four-fold symmetry for the resonance
+field in the (100) grown film. In addition, the value of effective
+magnetization (4{\pi}Meff) and extrinsic linewidth ({\Delta}H0) are observed to
+be dependent on substrate orientation. Hence PLD growth can assist
+single-crystalline YIG and BYG films with a perfect interface that can be used
+for spintronics and related device applications.",2109.05901v1
+2014-08-13,Quantitative Temperature Dependence of Longitudinal Spin Seebeck Effect at High Temperatures,"This article reports temperature-dependent measurements of longitudinal spin
+Seebeck effects (LSSEs) in Pt/Y$_3$Fe$_5$O$_{12}$ (YIG)/Pt systems in a high
+temperature range from room temperature to above the Curie temperature of YIG.
+The experimental results show that the magnitude of the LSSE voltage in the
+Pt/YIG/Pt systems rapidly decreases with increasing the temperature and
+disappears above the Curie temperature. The critical exponent of the LSSE
+voltage in the Pt/YIG/Pt systems at the Curie temperature was estimated to be
+3, which is much greater than that for the magnetization curve of YIG. This
+difference highlights the fact that the mechanism of the LSSE cannot be
+explained in terms of simple static magnetic properties in YIG.",1408.2972v2
+2016-04-24,Who pumps spin current into nonmagnetic-metal (NM) layer in YIG/NM multilayers at ferromagnetic resonance?,"Spin pumping in Yttrium-iron-garnet (YIG)/nonmagnetic-metal (NM) layer
+systems under ferromagnetic resonance (FMR) conditions is a popular method of
+generating spin current in the NM layer. A good understanding of the spin
+current source is essential in extracting spin Hall angle of the NM and in
+potential spintronics applications. It is widely believed that spin current is
+pumped from precessing YIG magnetization into NM layer. Here, by combining
+microwave absorption and DC-voltage measurements on YIG/Pt and YIG/NM1/NM2
+(NM1=Cu or Al, NM2=Pt or Ta), we unambiguously showed that spin current in NM
+came from the magnetized NM surface (in contact with YIG) due to the magnetic
+proximity effect (MPE), rather than the precessing YIG magnetization. This
+conclusion is reached through our unique detecting method where the FMR
+microwave absorption of the magnetized NM surface, hardly observed in the
+conventional FMR experiments, was greatly amplified when the electrical
+detection circuit was switched on.",1604.07025v1
+2016-10-24,Tunable sign change of spin Hall magnetoresistance in Pt/NiO/YIG structures,"Spin Hall magnetoresistance (SMR) has been investigated in Pt/NiO/YIG
+structures in a wide range of temperature and NiO thickness. The SMR shows a
+negative sign below a temperature which increases with the NiO thickness. This
+is contrary to a conventional SMR theory picture applied to Pt/YIG bilayer
+which always predicts a positive SMR. The negative SMR is found to persist even
+when NiO blocks the spin transmission between Pt and YIG, indicating it is
+governed by the spin current response of NiO layer. We explain the negative SMR
+by the NiO 'spin-flop' coupled with YIG, which can be overridden at higher
+temperatures by positive SMR contribution from YIG. This highlights the role of
+magnetic structure in antiferromagnets for transport of pure spin current in
+multilayers.",1610.07362v2
+2022-04-12,Spin Peltier effect and its length scale in Pt/YIG system at high temperatures,"The temperature and yttrium-iron-garnet (YIG) thickness dependences of the
+spin Peltier effect (SPE) have been investigated using a Pt/YIG junction system
+at temperatures ranging from room temperature to the Curie temperature of YIG
+by the lock-in thermography method. By analyzing the YIG thickness dependence
+using an exponential decay model, the characteristic length of SPE in YIG is
+estimated to be 0.9 $\mu$m near room temperature and almost constant even near
+the Curie temperature. The high-temperature behavior of SPE is clearly
+different from that of the spin Seebeck effect, providing a clue for
+microscopically understanding the reciprocal relation between them.",2204.05482v1
+2015-03-20,Control of spin current by a magnetic YIG substrate in NiFe/Al nonlocal spin valves,"We study the effect of a magnetic insulator (Yttrium Iron Garnet - YIG)
+substrate on the spin transport properties of Ni$_{80}$Fe$_{20}$/Al nonlocal
+spin valve (NLSV) devices. The NLSV signal on the YIG substrate is about 2 to 3
+times lower than that on a non magnetic SiO$_2$ substrate, indicating that a
+significant fraction of the spin-current is absorbed at the Al/YIG interface.
+By measuring the NLSV signal for varying injector-to-detector distance and
+using a three dimensional spin-transport model that takes spin current
+absorption at the Al/YIG interface into account we obtain an effective
+spin-mixing conductance $G_{\uparrow\downarrow}\simeq 5 - 8\times
+10^{13}~\Omega^{-1}$m$^{-2}$. We also observe a small but clear modulation of
+the NLSV signal when rotating the YIG magnetization direction with respect to
+the fixed spin polarization of the spin accumulation in the Al. Spin relaxation
+due to thermal magnons or roughness of the YIG surface may be responsible for
+the observed small modulation of the NLSV signal.",1503.06108v1
+2017-11-21,Ionic Modulation of Interfacial Magnetism through Electrostatic Doping in Pt/YIG bilayer heterostructure,"Voltage modulation of yttrium iron garnet (YIG) with compactness, high speed
+response, energy efficiency and both practical/theoretical siginificances can
+be widely applied to various YIG based spintronics such as spin Hall, spin
+pumping, spin Seeback effects. Here we initial an ionic modulation of
+interfacial magnetism process on YIG/Pt bilayer heterostructures, where the Pt
+capping would influence the ferromagnetic (FMR) field position significantly,
+and realize a significant magnetism enhancement in bilayer system. A large
+voltage induced FMR field shifts of 690 Oe has been achieved in YIG (13 nm)/Pt
+(3 nm) multilayer heterostructures under a small voltage bias of 4.5 V. The
+remarkable ME tunability comes from voltage induced extra FM ordering in Pt
+metal layer near the Pt/YIG interface. The first-principle theoretical
+simulation reveal that the electrostatic doping induced Pt5+ ions have strong
+magnetic ordering due to uncompensated d orbit electrons. The large voltage
+control of FMR change pave a foundation towards novel voltage tunable YIG based
+spintronics.",1711.07610v3
+2018-04-19,Effect of magnons on interfacial phonon drag in YIG/metal systems,"We examine substrate-to-film interfacial phonon drag on typical spin Seebeck
+heterostructures, in particular studying the effect of ferromagnetic magnons on
+the phonon-electron drag dynamics at the interface. We investigate with high
+precision the effect of magnons in the Pt|YIG heterostructure by designing a
+magnon drag thermocouple; a hybrid sample with both a Pt|YIG film and Pt|GGG
+interface accessible isothermally via a 6 nm Pt film patterned in a rectangular
+U shape with one arm on the 250 nm YIG film and the other on GGG. We measure
+the voltage between the isothermal ends of the U, while applying a temperature
+gradient parallel to the arms and perpendicular to the bottom connection. With
+a uniform applied temperature gradient, the Pt acts as a differential
+thermocouple. We conduct temperature-dependent longitudinal thermopower
+measurements on this sample. Results show that the YIG interface actually
+decreases the thermopower of the film, implying that magnons impede phonon
+drag. We repeat the experiment using metals with low spin Hall angles, Ag and
+Al, in place of Pt. We find that the phonon drag peak in thermopower is killed
+in samples where the metallic interface is with YIG. We also investigate
+magneto-thermopower and YIG film thickness dependence. These measurements
+confirm our findings that magnons impede the phonon-electron drag interaction
+at the metallic interface in these heterostructures.",1804.07023v1
+2018-10-16,Spin-wave-induced lateral temperature gradient in a YIG thin film/GGG system excited in an ESR cavity,"Lateral thermal gradient of an yttrium iron garnet (YIG) film under the
+microwave application in the cavity of the electron spin resonance system (ESR)
+was measured at room temperature by fabricating a Cu/Sb thermocouple onto it.
+To date, thermal transport in YIG films caused by the Damon-Eshbach mode (DEM)
+- the unidirectional spin-wave heat conveyer effect - was demonstrated only by
+the excitation using coplanar waveguides. Here we show that effect exists even
+under YIG excitation using the ESR cavity - tool often employed to realize spin
+pumping. The temperature difference observed around the ferromagnetic resonance
+(FMR) field under the 4 mW microwave power peaked at 13 mK. The observed
+thermoelectric signal indicates the imbalance of the population between the
+DEMs that propagate near the top and bottom surfaces of the YIG film. We
+attribute the DEM population imbalance to the different magnetic damping near
+the top and bottom YIG surfaces. Additionally, the spin wave dynamics of the
+system were investigated using the micromagnetic simulations. The micromagnetic
+simulations confirmed the existence of the DEM imbalance in the system with the
+increased Gilbert damping at one of the YIG interfaces. The reported results
+are indispensable for the quantitative estimation of the electromotive force in
+the spin-charge conversion experiments using ESR cavities.",1810.06875v1
+2021-12-21,Fast long-wavelength exchange spin waves in partially-compensated Ga:YIG,"Spin waves in yttrium iron garnet (YIG) nano-structures attract increasing
+attention from the perspective of novel magnon-based data processing
+applications. For short wavelengths needed in small-scale devices, the group
+velocity is directly proportional to the spin-wave exchange stiffness constant
+$\lambda_\mathrm{ex}$. Using wave vector resolved Brillouin Light Scattering
+(BLS) spectroscopy, we directly measure $\lambda_\mathrm{ex}$ in Ga-substituted
+YIG thin films and show that it is about three times larger than for pure YIG.
+Consequently, the spin-wave group velocity overcomes the one in pure YIG for
+wavenumbers $k > 4$ rad/$\mu$m, and the ratio between the velocities reaches a
+constant value of around 3.4 for all $k > 20$ rad/$\mu$m. As revealed by
+vibrating-sample magnetometry (VSM) and ferromagnetic resonance (FMR)
+spectroscopy, Ga:YIG films with thicknesses down to 59 nm have a low Gilbert
+damping ($\alpha < 10^{-3}$), a decreased saturation magnetization $\mu_0
+M_\mathrm{S}~\approx~20~$mT and a pronounced out-of-plane uniaxial anisotropy
+of about $\mu_0 H_{\textrm{u1}} \approx 95 $ mT which leads to an out-of-plane
+easy axis. Thus, Ga:YIG opens access to fast and isotropic spin-wave transport
+for all wavelengths in nano-scale systems independently of dipolar effects.",2112.11348v1
+2011-08-22,Acoustic spin pumping: Direct generation of spin currents from sound waves in Pt/Y3Fe5O12 hybrid structures,"Using a Pt/Y3Fe5O12 (YIG) hybrid structure attached to a piezoelectric
+actuator, we demonstrate the generation of spin currents from sound waves. This
+""acoustic spin pumping"" (ASP) is caused by the sound wave generated by the
+piezoelectric actuator, which then modulates the distribution function of
+magnons in the YIG layer and results in a pure-spin-current injection into the
+Pt layer across the Pt/YIG interface. In the Pt layer, this injected spin
+current is converted into an electric voltage due to the inverse spin-Hall
+effect (ISHE). The ISHE voltage induced by the ASP is detected by measuring
+voltage in the Pt layer at the piezoelectric resonance frequency of the
+actuator coupled with the Pt/YIG system. The frequency-dependent measurements
+enable us to separate the ASP-induced signals from extrinsic heating effects.
+Our model calculation based on the linear response theory provides us with a
+qualitative and quantitative understanding of the ASP in the Pt/YIG system.",1108.4238v1
+2015-01-12,Anomalous Hall effect in YIG$|$Pt bilayers,"We measure the ordinary and the anomalous Hall effect in a set of yttrium
+iron garnet$|$platinum (YIG$|$Pt) bilayers via magnetization orientation
+dependent magnetoresistance experiments. Our data show that the presence of the
+ferrimagnetic insulator YIG leads to an anomalous Hall like signature in Pt,
+sensitive to both Pt thickness and temperature. Interpretation of the
+experimental findings in terms of the spin Hall anomalous Hall effect indicates
+that the imaginary part of the spin mixing interface conductance
+$G_{\mathrm{i}}$ plays a crucial role in YIG$|$Pt bilayers. In particular, our
+data suggest a sign change in $G_{\mathrm{i}}$ between $10\,\mathrm{K}$ and
+$300\,\mathrm{K}$. Additionally, we report a higher order Hall effect, which
+appears in thin Pt films on YIG at low temperatures.",1501.02574v3
+2015-03-19,Critical suppression of spin Seebeck effect by magnetic fields,"The longitudinal spin Seebeck effect (LSSE) in Pt/Y$_3$Fe$_5$O$_{12}$ (YIG)
+junction systems has been investigated at various magnetic fields and
+temperatures. We found that the LSSE voltage in a Pt/YIG-slab system is
+suppressed by applying high magnetic fields and this suppression is critically
+enhanced at low temperatures. The field-induced suppression of the LSSE in the
+Pt/YIG-slab system is too large at around room temperature to be explained
+simply by considering the effect of the Zeeman gap in magnon excitation. This
+result requires us to introduce magnon-frequency-dependent mechanism into the
+scenario of LSSE; low-frequency magnons dominantly contribute to the LSSE. The
+magnetic field dependence of the LSSE voltage was observed to change by
+changing the thickness of YIG, suggesting that the thermo-spin conversion by
+the low-frequency magnons is suppressed in thin YIG films due to the long
+characteristic lengths of such magnons.",1503.05764v2
+2015-10-30,Pure spin-Hall magnetoresistance in Rh/Y3Fe5O12 hybrid,"We report an investigation of anisotropic magnetoresistance (AMR) and
+anomalous Hall resistance (AHR) of Rh and Pt thin films sputtered on epitaxial
+Y$_3$Fe$_5$O$_{12}$ (YIG) ferromagnetic insulator films. For the Pt/YIG hybrid,
+large spin-Hall magnetoresistance (SMR) along with a sizable conventional
+anisotropic magnetoresistance (CAMR) and a nontrivial temperature dependence of
+AHR were observed in the temperature range of 5-300 K. In contrast, a reduced
+SMR with negligible CAMR and AHR was found in Rh/YIG hybrid. Since CAMR and AHR
+are characteristics for all ferromagnetic metals, our results suggest that the
+Pt is likely magnetized by YIG due to the magnetic proximity effect (MPE) while
+Rh remains free of MPE. Thus the Rh/YIG hybrid could be an ideal model system
+to explore physics and devices associated with pure spin current.",1510.09007v1
+2016-03-30,Low-damping transmission of spin waves through YIG/Pt-based layered structures for spin-orbit-torque applications,"We show that in YIG-Pt bi-layers, which are widely used in experiments on the
+spin transfer torque and spin Hall effects, the spin-wave amplitude
+significantly decreases in comparison to a single YIG film due to the
+excitation of microwave eddy currents in a Pt coat. By introducing a novel
+excitation geometry, where the Pt layer faces the ground plane of a microstrip
+line structure, we suppressed the excitation of the eddy currents in the Pt
+layer and, thus, achieved a large increase in the transmission of the
+Damon-Eshbach surface spin wave. At the same time, no visible influence of an
+external dc current applied to the Pt layer on the spin-wave amplitude in the
+YIG-Pt bi-layer was observed in our experiments with YIG films of micrometer
+thickness.",1603.09201v1
+2016-08-03,Influence of yttrium iron garnet thickness and heater opacity on the nonlocal transport of electrically and thermally excited magnons,"We studied the nonlocal transport behavior of both electrically and thermally
+excited magnons in yttrium iron garnet (YIG) as a function of its thickness.
+For electrically injected magnons, the nonlocal signals decrease monotonically
+as the YIG thickness increases. For the nonlocal behavior of the thermally
+generated magnons, or the nonlocal spin Seebeck effect (SSE), we observed a
+sign reversal which occurs at a certain heater-detector distance, and it is
+influenced by both the opacity of the YIG/heater interface and the YIG
+thickness. Our nonlocal SSE results can be qualitatively explained by the
+bulk-driven SSE mechanism together with the magnon diffusion model. Using a
+two-dimensional finite element model (2D-FEM), we estimated the bulk spin
+Seebeck coefficient of YIG at room temperature. The quantitative disagreement
+between the experimental and modeled results indicates more complex processes
+going on in addition to magnon diffusion and relaxation, especially close to
+the contacts.",1608.01178v1
+2017-02-22,Is spin superfluidity possible in YIG films?,"Recently it was suggested that stationary spin supercurrents (spin
+superfluidity) are possible in the magnon condensate observed in
+yttrium-iron-garnet (YIG) magnetic films under strong external pumping. Here we
+analyze this suggestion. From topology of the equilibrium order parameter in
+YIG one must not expect energetic barriers making spin supercurrents
+metastable. However some small barriers of dynamical origin are possible
+nevertheless. The critical phase gradient (analog of the Landau critical
+velocity in superfluids) is proportional to intensity of the coherent spin wave
+(number of condensed magnons). The conclusion is that although spin
+superfluidity in YIG films is possible in principle, the published claim of its
+observation is not justified.
+  The analysis revealed that the widely accepted spin-wave spectrum in YIG
+films with magnetostatic and exchange interaction required revision. This led
+to revision of non-linear corrections, which determine stability of the magnon
+condensate with and without spin supercurrents.",1702.06994v2
+2017-06-23,Detection of induced paramagnetic moments in Pt on Y$_3$Fe$_5$O$_{12}$ via x-ray magnetic circular dichroism,"Magnetic moments in an ultra-thin Pt film on a ferrimagnetic insulator
+Y$_3$Fe$_5$O$_{12}$ (YIG) have been investigated at high magnetic fields and
+low temperatures by means of X-ray magnetic circular dichroism (XMCD). We
+observed an XMCD signal due to the magnetic moments in a Pt film at the Pt
+$L_{3}$- and $L_{2}$-edges. By means of the element-specific magnetometry, we
+found that the XMCD signal at the Pt $L_{3}$-edge gradually increases with
+increasing the magnetic field even when the field is much greater than the
+saturation field of YIG. Importantly, the observed XMCD intensity was found to
+be much greater than the intensity expected from the Pauli paramagnetism of Pt
+when the Pt film is attached to YIG. These results imply the emergence of
+induced paramagnetic moments in Pt on YIG and explain the characteristics of
+the unconventional Hall effect in Pt/YIG systems.",1706.07559v1
+2017-12-07,Spin waves in coupled YIG/Co heterostructures,"We investigate yttrium iron garnet (YIG)/cobalt (Co) heterostructures using
+broadband ferromagnetic resonance (FMR). We observe an efficient excitation of
+perpendicular standing spin waves (PSSWs) in the YIG layer when the resonance
+frequencies of the YIG PSSWs and the Co FMR line coincide. Avoided crossings of
+YIG PSSWs and the Co FMR line are found and modeled using mutual spin pumping
+and exchange torques. The excitation of PSSWs is suppressed by a thin aluminum
+oxide (AlOx) interlayer but persists with a copper (Cu) interlayer, in
+agreement with the proposed model.",1712.02561v1
+2018-11-04,Role of gallium diffusion in the formation of a magnetically dead layer at Y3Fe5O12 / Gd3Ga5O12 epitaxial interface,"We have clarified the origin of magnetically dead interface layer formed in
+yttrium iron garnet (YIG) films grown at above 700{\deg}C onto gadolinium
+gallium garnet (GGG) substrate by means of laser molecular beam epitaxy. The
+diffusion-assisted formation of a Ga-rich region at the YIG / GGG interface is
+demonstrated by means of composition depth profiling performed by X-ray
+photoelectron spectroscopy, secondary ion mass spectroscopy and X-ray and
+neutron reflectometry. Our finding is in sharp contrast to the earlier
+expressed assumption that Gd acts as a migrant element in the YIG/GGG system.
+We further correlate the presence of Ga-rich transition layer with considerable
+quenching of ferromagnetic resonance and spin wave propagation in thin YIG
+films. Finally, we clarify the origin of the enigmatic low-density overlayer
+that is often observed in neutron and X-ray reflectometry studies of the YIG /
+GGG epitaxial system.",1811.01321v2
+2018-11-13,Experimental proof of the reciprocal relation between spin Peltier and spin Seebeck effects in a bulk YIG/Pt bilayer,"We verify for the first time the reciprocal relation between the spin Peltier
+and spin Seebeck effects in a bulk YIG/Pt bilayer. Both experiments are
+performed on the same YIG/Pt device by a setup able to accurately determine
+heat currents and to separate the spin Peltier heat from the Joule heat
+background. The sample-specific value for the characteristics of both effects
+measured on the present YIG/Pt bilayer is $(6.2 \pm 0.4)\times 10^{-3} \,\,
+\mbox{KA$^{-1}$}$. In the paper we also discuss the relation of both effects
+with the intrinsic and extrinsic parameters of YIG and Pt and we envisage
+possible strategies to optimize spin Peltier refrigeration.",1811.05120v1
+2019-03-06,Microwave magnon damping in YIG films at millikelvin temperatures,"Magnon systems used in quantum devices require low damping if coherence is to
+be maintained. The ferrimagnetic electrical insulator yttrium iron garnet (YIG)
+has low magnon damping at room temperature and is a strong candidate to host
+microwave magnon excitations in future quantum devices. Monocrystalline YIG
+films are typically grown on gadolinium gallium garnet (GGG) substrates. In
+this work, comparative experiments made on YIG waveguides with and without GGG
+substrates indicate that the material plays a significant role in increasing
+the damping at low temperatures. Measurements reveal that damping due to
+temperature-peak processes is dominant above 1 K. Damping behaviour that we
+show can be attributed to coupling to two-level fluctuators (TLFs) is observed
+below 1 K. Upon saturating the TLFs in the substrate-free YIG at 20 mK,
+linewidths of 1.4 MHz are achievable: lower than those measured at room
+temperature.",1903.02527v3
+2019-03-28,Acoustic excitation and electrical detection of spin waves and spin currents in hypersonic bulk waves resonator with YIG/Pt system,"We report on the self-consisted semi-analytical theory of magnetoelastic
+excitation and electrical detection of spin waves and spin currents in
+hypersonic bulk acoustic waves resonator with ZnO-GGG-YIG/Pt layered structure.
+Electrical detection of acoustically driven spin waves occurs due to spin
+pumping from YIG to Pt and inverse spin Hall (ISHE) effect in Pt as well as due
+to electrical response of ZnO piezotransducer. The frequency-field dependences
+of the resonator frequencies and ISHE voltage $U_{ISHE}$ are correlated with
+experimental ones observed previously. Their fitting allows to determine some
+magnetic and magnetoelastic parameters of YIG. The analysis of the YIG film
+thickness influence on $U_{ISHE}$ gives the possibility to find the optimal
+thickness for maximal $U_{ISHE}$ value.",1903.12130v2
+2019-06-04,Thickness dependence of spin Peltier effect visualized by thermal imaging technique,"Magnon propagation length in a ferrimagnetic insulator yttrium iron garnet
+(YIG) has been investigated by measuring and analyzing the YIG-thickness t_YIG
+dependence of the spin Peltier effect (SPE) in a Pt/YIG junction system. By
+means of the lock-in thermography technique, we measured the spatial
+distribution of the SPE-induced temperature modulation in the Pt/YIG system
+with the t_YIG gradation, allowing us to obtain the accurate t_YIG dependence
+of SPE with high t_YIG resolution. Based on the t_YIG dependence of SPE, we
+verified the applicability of several phenomenological models to estimate the
+magnon diffusion length in YIG.",1906.01560v3
+2020-10-24,Octave-Tunable Magnetostatic Wave YIG Resonators on a Chip,"We have designed, fabricated, and characterized magnetostatic wave (MSW)
+resonators on a chip. The resonators are fabricated by patterning
+single-crystal yttrium iron garnet (YIG) film on a gadolinium gallium garnet
+(GGG) substrate and excited by loop-inductor transducers. We achieved this
+technology breakthrough by developing a YIG film etching process and
+fabricating thick aluminum coplanar waveguide (CPW) inductor loop around each
+resonator to individually address and excite MSWs. At 4.77 GHz, the 0.68 square
+mm resonator achieves a quality factor Q > 5000 with a bias field of 987 Oe. We
+also demonstrate YIG resonator tuning by more than one octave from 3.63 to 7.63
+GHz by applying an in-plane external magnetic field. The measured quality
+factor of the resonator is consistently over 3000 above 4 GHz. The
+micromachining technology enables the fabrication of multiple single- and
+two-port YIG resonators on the same chip with all resonators demonstrating
+octave tunability and high Q .",2010.12732v1
+2021-09-24,Damping in yttrium iron garnet film with an interface,"We report strong damping enhancement in a 200 nm thick yttrium iron garnet
+(YIG) film due to spin inhomogeneity at the interface. The growth-induced thin
+interfacial gadolinium iron garnet (GdIG) layer antiferromagnetically (AFM)
+exchange couples with the rest of the YIG layer. The out-of-plane angular
+variation of ferromagnetic resonance (FMR) linewidth $\Delta H$ reflects a
+large inhomogeneous distribution of effective magnetization $\Delta 4 \pi
+M_{eff}$ due to the presence of an exchange springlike moments arrangement in
+YIG. We probe the spin inhomogeneity at the YIG-GdIG interface by performing an
+in-plane angular variation of resonance field $H_{r}$, leading to a
+unidirectional feature. The large extrinsic $\Delta 4\pi M_{eff}$ contribution,
+apart from the inherent intrinsic Gilbert contribution, manifests enhanced
+precessional damping in YIG film.",2109.12071v1
+2022-04-04,Inverse Orbital Torque via Spin-Orbital Entangled States,"While current-induced torque by orbital current has been experimentally found
+in various structures, evidence for its reciprocity has been missing so far.
+Here, we report experimental evidence of strong inverse orbital torque in
+YIG/Pt/CuOx (YIG = Y3Fe5O12) mediated by spin-orbital entangled electronic
+states in Pt. By injecting spin current from YIG to Pt by the spin pumping via
+ferromagnetic resonance and by the spin Seebeck effect, we find a pronounced
+inverse spin Hall effect-like signal. While a part of the signal is explained
+as due to the inverse spin-orbital Hall effect in Pt, we also find substantial
+increase of the signal in YIG/Pt/CuOx structures compared to the signal in
+YIG/Pt. We attribute this to the inverse orbital Rashba-Edelstein effect at
+Pt/CuOx interface mediated by the spin-orbital entangled states in Pt. Our work
+paves the way toward understanding of spin-orbital entangled physics in
+nonequilibrium and provides a way for electrical detection of the orbital
+current in orbitronic device applications.",2204.01825v2
+2024-02-22,Unraveling the origin of antiferromagnetic coupling at YIG/permalloy interface,"We investigate the structural and electronic origin of antiferromagnetic
+coupling in the Yttrium iron garnet (YIG) and permalloy (Py) bilayer system at
+the atomic level. Ferromagnetic Resonance (FMR) reveal unique hybrid modes in
+samples prepared with surface ion milling, indicative of antiferromagnetic
+exchange coupling at the YIG/Py interface. Using scanning transmission electron
+microscopy (STEM), we highlight significant interfacial differences introduced
+by ion-milling. The observations suggests that the antiferromagnetic coupling
+in YIG/Py bilayers is predominantly driven by an oxygen-mediated super-exchange
+coupling mechanism on the tetrahedral Fe terminated YIG surface, which is
+supported by density functional theory (DFT) calculations. This research
+provides critical insight into the fundamental mechanisms governing the
+efficiency of coupling in magnetic bilayers and underscores the pivotal role of
+oxide surface termination in modulating magnetic interfacial dynamics.",2402.14553v2
+2013-02-28,Spin mixing conductance at a well-controlled platinum/yttrium iron garnet interface,"A platinum (Pt)/yttrium iron garnet (YIG) bilayer system with a
+well-controlled interface has been developed; spin mixing conductance at the
+Pt/YIG interface has been studied. Crystal perfection at the interface is
+experimentally demonstrated to contribute to large spin mixing conductance. The
+spin mixing conductance is obtained to be $1.3\times10^{18} \rm{m^{-2}}$ at the
+well-controlled Pt/YIG interface, which is close to a theoretical prediction.",1302.7091v3
+2014-10-07,Influence of interface condition on spin-Seebeck effects,"The longitudinal spin-Seebeck effect (LSSE) has been investigated for
+Pt/yttrium iron garnet (YIG) bilayer systems. The magnitude of the voltage
+induced by the LSSE is found to be sensitive to the Pt/YIG interface condition.
+We observed large LSSE voltage in a Pt/YIG system with a better crystalline
+interface, while the voltage decays steeply when an amorphous layer is
+introduced at the interface artificially.",1410.1655v1
+2016-12-19,Thickness dependence study of current-driven ferromagnetic resonance in Y3Fe5O12/heavy metal bilayers,"We use ferromagnetic resonance to study the current-induced torques in
+YIG/heavy metal bilayers. YIG samples with thickness varying from 14.8 nm to 80
+nm, with Pt or Ta thin film on top, are measured by applying a microwave
+current into the heavy metals and measuring the longitudinal DC voltage
+generated by both spin rectification and spin pumping. From a symmetry analysis
+of the FMR lineshape and its dependence on YIG thickness, we deduce that the
+Oersted field dominates over spin-transfer torque in driving magnetization
+dynamics.",1612.06111v1
+2018-03-10,Atomic-scale structure and chemistry of YIG/GGG Interface,"Y3Fe5O12 (YIG) is a promising candidate for spin wave devices. In the thin
+film devices, the interface between YIG and substrate may play important roles
+in determining the device properties. Here, we use spherical
+aberration-corrected scanning electron microscopy and spectroscopy to study the
+atomic arrangement, chemistry and electronic structure of the YIG/Gd3Ga5O12
+(GGG) interface. We find that the chemical bonding of the interface is
+FeO-GdGaO and the interface remains sharp in both atomic and electronic
+structures. These results provide necessary information for understanding the
+properties of interface and also for atomistic calculation.",1803.03799v1
+2024-01-17,A Distributed Magnetostatic Resonator,"This work reports the design, fabrication, and characterization of
+coupling-enhanced magnetostatic forward volume wave resonators with significant
+spur suppression. The fabrication is based on surface micro-machining of
+yttrium iron garnet (YIG) film on a gadolinium gallium garnet (GGG) substrate
+with thick gold transducers. A distributed resonator is used to excite forward
+volume waves in YIG to realize a frequency dependent coupling boost. Fabricated
+devices at 18 GHz and 7 GHz show coupling coefficients as high as 13$\%$ and
+quality factors above 1000. Higher-order magnetostatic mode suppression is
+experimentally demonstrated through a combination of transducer and YIG
+geometry design. An edge-coupling filter topology is proposed and simulated
+which utilizes this novel distributed magnetostatic resonator.",2401.08911v1
+2013-08-17,Thickness and power dependence of the spin-pumping effect in Y3Fe5O12/Pt heterostructures measured by the inverse spin Hall effect,"The dependence of the spin-pumping effect on the yttrium iron garnet
+(Y3Fe5O12, YIG) thickness detected by the inverse spin Hall effect (ISHE) has
+been investigated quantitatively. Due to the spin-pumping effect driven by the
+magnetization precession in the ferrimagnetic insulator YIG film a
+spin-polarized electron current is injected into the Pt layer. This spin
+current is transformed into electrical charge current by means of the ISHE. An
+increase of the ISHE-voltage with increasing film thickness is observed and
+compared to the theoretically expected behavior. The effective damping
+parameter of the YIG/Pt samples is found to be enhanced with decreasing YIG
+film thickness. The investigated samples exhibit a spin mixing conductance of
+g=(7.43 \pm 0.36) \times 10^{18} m^{-2} and a spin Hall angle of theta_{ISHE} =
+0.009 \pm 0.0008. Furthermore, the influence of nonlinear effects on the
+generated voltage and on the Gilbert damping parameter at high excitation
+powers are revealed. It is shown that for small YIG film thicknesses a
+broadening of the linewidth due to nonlinear effects at high excitation powers
+is suppressed because of a lack of nonlinear multi-magnon scattering channels.
+We have found that the variation of the spin-pumping efficiency for thick YIG
+samples exhibiting pronounced nonlinear effects is much smaller than the
+nonlinear enhancement of the damping.",1308.3787v1
+2014-02-15,Measurement of the intrinsic damping constant in individual nanodisks of YIG and YIG{\textbar}Pt,"We report on an experimental study on the spin-waves relaxation rate in two
+series of nanodisks of diameter $\phi=$300, 500 and 700~nm, patterned out of
+two systems: a 20~nm thick yttrium iron garnet (YIG) film grown by pulsed laser
+deposition either bare or covered by 13~nm of Pt. Using a magnetic resonance
+force microscope, we measure precisely the ferromagnetic resonance linewidth of
+each individual YIG and YIG{\textbar}Pt nanodisks. We find that the linewidth
+in the nanostructure is sensibly smaller than the one measured in the extended
+film. Analysis of the frequency dependence of the spectral linewidth indicates
+that the improvement is principally due to the suppression of the inhomogeneous
+part of the broadening due to geometrical confinement, suggesting that only the
+homogeneous broadening contributes to the linewidth of the nanostructure. For
+the bare YIG nano-disks, the broadening is associated to a damping constant
+$\alpha = 4 \cdot 10^{-4}$. A 3 fold increase of the linewidth is observed for
+the series with Pt cap layer, attributed to the spin pumping effect. The
+measured enhancement allows to extract the spin mixing conductance found to be
+$G_{\uparrow \downarrow}= 1.55 \cdot 10^{14}~ \Omega^{-1}\text{m}^{-2}$ for our
+YIG(20nm){\textbar}Pt interface, thus opening large opportunities for the
+design of YIG based nanostructures with optimized magnetic losses.",1402.3630v1
+2016-04-29,Spin Seebeck effect through antiferromagnetic NiO,"We report temperature-dependent spin-Seebeck measurements on Pt/YIG bilayers
+and Pt/NiO/YIG trilayers, where YIG (Yttrium iron garnet, Y$_3$Fe$_5$O$_{12}$)
+is an insulating ferrimagnet and NiO is an antiferromagnet at low temperatures.
+The thickness of the NiO layer is varied from 0 to 10 nm. In the Pt/YIG
+bilayers, the temperature gradient applied to the YIG stimulates dynamic spin
+injection into the Pt, which generates an inverse spin Hall voltage in the Pt.
+The presence of a NiO layer dampens the spin injection exponentially with a
+decay length of $2 \pm 0.6$ nm at 180 K. The decay length increases with
+temperature and shows a maximum of $5.5 \pm 0.8$ nm at 360 K. The temperature
+dependence of the amplitude of the spin-Seebeck signal without NiO shows a
+broad maximum of $6.5 \pm 0.5$ $\mu$V/K at 20 K. In the presence of NiO, the
+maximum shifts sharply to higher temperatures, likely correlated to the
+increase in decay length. This implies that NiO is most transparent to magnon
+propagation near the paramagnet-antiferromagnet transition. We do not see the
+enhancement in spin current driven into Pt reported in other papers when 1-2 nm
+NiO layers are sandwiched between Pt and YIG.",1604.08659v2
+2016-08-16,Probing current-induced magnetic fields in Au|YIG heterostructure with low-energy muon spectroscopy,"We investigated the depth dependence of current-induced magnetic fields in a
+bilayer of a normal metal (Au) and a ferrimagnetic insulator (Yttrium Iron
+Garnet - YIG) by using low energy muon spectroscopy (LE-muSR). This allows us
+to explore how these fields vary from the Au surface down to the buried Au|YIG
+interface, which is relevant to study physics like the spin-Hall effect. We
+observed a maximum shift of 0.4 G in the internal field of muons at the surface
+of Au film which is in close agreement to the value expected for Oersted
+fields. As muons are implanted closer to the Au|YIG interface the shift is
+strongly suppressed, which we attribute to the dipolar fields present at the
+Au|YIG interface. Combining our measurements with modelling, we show that
+dipolar fields caused by the finite roughness of the Au|YIG interface
+consistently explains our observations. Our results, therefore, gauge the
+limits on the spatial resolution and the sensitivity of LE-muSR to the
+roughness of the buried magnetic interfaces, a prerequisite for future studies
+addressing current induced fields caused by the spin-Hall effect.",1608.04584v1
+2016-12-24,Impact of the interface quality of Pt/YIG(111) hybrids on their spin Hall magnetoresistance,"We study the influence of the interface quality of
+Pt/Y$_3$Fe$_5$O$_{12}$(111) hybrids on their spin Hall magnetoresistance. This
+is achieved by exposing Y$_3$Fe$_5$O$_{12}$(111) single crystal substrates to
+different well-defined surface treatments prior to the Pt deposition. The
+quality of the Y$_3$Fe$_5$O$_{12}$(YIG) surface, the Pt/YIG interface and the
+Pt layer is monitored \textit{in-situ} by reflection high-energy electron
+diffraction and Auger electron spectroscopy as well as \textit{ex-situ} by
+atomic force microscopy and x-ray diffraction. To identify the impact of the
+different surface treatments on the spin Hall magnetoresistance,
+angle-dependent magnetoresistance measurements are carried out at room
+temperature. The largest spin Hall magnetoresistance is found in Pt/YIG
+fabricated by a two-step surface treatment consisting of a ""piranha"" etch
+process followed by an annealing step at $500^\circ$C in pure oxygen
+atmosphere. Our data suggest that the small SMR in Pt/YIG without any surface
+treatments of the YIG substrate prior to Pt deposition is caused by a
+considerable carbon agglomeration at the Y$_3$Fe$_5$O$_{12}$ surface.",1612.08150v1
+2018-03-30,Nonlocal magnon spin transport in yttrium iron garnet with tantalum and platinum spin injection/detection electrodes,"We study the magnon spin transport in the magnetic insulator yttrium iron
+garnet (YIG) in a nonlocal experiment and compare the magnon spin excitation
+and detection for the heavy metal paramagnetic electrodes platinum (Pt|YIG|Pt)
+and tantalum (Ta|YIG|Ta). The electrical injection and detection processes rely
+on the (inverse) spin Hall effect in the heavy metals and the conversion
+between the electron spin and magnon spin at the heavy metal|YIG interface. Pt
+and Ta possess opposite signs of the spin Hall angle. Furthermore, their
+heterostructures with YIG have different interface properties, i.e. spin mixing
+conductances. By varying the distance between injector and detector, the magnon
+spin transport is studied. Using a circuit model based on the
+diffusion-relaxation transport theory, a similar magnon relaxation length of ~
+10 \mu m was extracted from both Pt and Ta devices. By changing the injector
+and detector material from Pt to Ta, the influence of interface properties on
+the magnon spin transport has been observed. For Ta devices on YIG the spin
+mixing conductance is reduced compared with Pt devices, which is quantitatively
+consistent when comparing the dependence of the nonlocal signal on the
+injector-detector distance with the prediction from the circuit model.",1803.11382v1
+2018-08-17,Temperature Dependence of Magnetic Properties of an 18-nm-thick YIG Film Grown by Liquid Phase Epitaxy: Effect of a Pt Overlayer,"Liquid phase epitaxy of an 18 nm thick Yttrium Iron garnet (YIG) film is
+achieved. Its magnetic properties are investigated in the 100 -- 400 K
+temperature range, as well as the influence of a 3 nm thick Pt overlayer on
+them. The saturation magnetization and the magnetocrystalline cubic anisotropy
+of the bare YIG film behave similarly to bulk YIG. A damping parameter of only
+a few $10^{-4}$ is measured, together with a low inhomogeneous contribution to
+the ferromagnetic resonance linewidth. The magnetic relaxation increases upon
+decreasing temperature, which can be partly ascribed to impurity relaxation
+mechanisms. While it does not change its cubic anisotropy, the Pt capping
+strongly affects the uniaxial perpendicular anisotropy of the YIG film, in
+particular at low temperatures. The interfacial coupling in the YIG/Pt
+heterostructure is also revealed by an increase of the linewidth, which
+substantially grows by lowering the temperature.",1808.05785v2
+2020-04-05,Spin wave based tunable switch between superconducting flux qubits,"Quantum computing hardware has received world-wide attention and made
+considerable progress recently. YIG thin film have spin wave (magnon) modes
+with low dissipation and reliable control for quantum information processing.
+However, the coherent coupling between a quantum device and YIG thin film has
+yet been demonstrated. Here, we propose a scheme to achieve strong coupling
+between superconducting flux qubits and magnon modes in YIG thin film. Unlike
+the direct $\sqrt{N}$ enhancement factor in coupling to the Kittel mode or
+other spin ensembles, with N the total number of spins, an additional spatial
+dependent phase factor needs to be considered when the qubits are magnetically
+coupled with the magnon modes of finite wavelength. To avoid undesirable
+cancelation of coupling caused by the symmetrical boundary condition, a CoFeB
+thin layer is added to one side of the YIG thin film to break the symmetry. Our
+numerical simulation demonstrates avoided crossing and coherent transfer of
+quantum information between the flux qubits and the standing spin waves in YIG
+thin films. We show that the YIG thin film can be used as a tunable switch
+between two flux qubits, which have modified shape with small direct inductive
+coupling between them. Our results manifest that it is possible to couple flux
+qubits while suppressing undesirable cross-talk.",2004.02156v1
+2021-04-16,Strong magnon-photon coupling with chip-integrated YIG in the zero-temperature limit,"The cross-integration of spin-wave and superconducting technologies is a
+promising method for creating novel hybrid devices for future information
+processing technologies to store, manipulate, or convert data in both classical
+and quantum regimes. Hybrid magnon-polariton systems have been widely studied
+using bulk Yttrium Iron Garnet (Y$_{3}$Fe$_{5}$O$_{12}$, YIG) and
+three-dimensional microwave photon cavities. However, limitations in YIG growth
+have thus far prevented its incorporation into CMOS compatible technology such
+as high quality factor superconducting quantum technology. To overcome this
+impediment, we have used Plasma Focused Ion Beam (PFIB) technology -- taking
+advantage of precision placement down to the micron-scale -- to integrate YIG
+with superconducting microwave devices. Ferromagnetic resonance has been
+measured at millikelvin temperatures on PFIB-processed YIG samples using planar
+microwave circuits. Furthermore, we demonstrate strong coupling between
+superconducting resonator and YIG ferromagnetic resonance modes by maintaining
+reasonably low loss while reducing the system down to the micron scale. This
+achievement of strong coupling on-chip is a crucial step toward fabrication of
+functional hybrid quantum devices that advantage from spin-wave and
+superconducting components.",2104.08068v3
+2019-02-01,Quantum thermodynamics of complex ferrimagnets,"High-quality magnets such as yttrium iron garnet (YIG) are electrically
+insulating and very complex. By implementing a quantum thermostat into
+atomistic spin dynamics we compute YIG's key thermodynamic properties, viz. the
+magnon power spectrum and specific heat, for a large temperature range. The
+results differ (sometimes spectacularly) from simple models and classical
+statistics, but agree with available experimental data.",1902.00449v1
+2012-11-01,Longitudinal Spin Seebeck Effect Free from the Proximity Nernst Effect,"This letter provides evidence for intrinsic longitudinal spin Seebeck effects
+(LSSEs) that are free from the anomalous Nernst effect (ANE) caused by an
+extrinsic proximity effect. We report the observation of LSSEs in Au/Y3Fe5O12
+(YIG) and Pt/Cu/YIG systems, showing that LSSE appears even when the mechanism
+of the proximity ANE is clearly removed. In the conventional Pt/YIG structure,
+furthermore, we separate the LSSE from the ANE by comparing the voltages in
+different magnetization and temperature-gradient configurations; the ANE
+contamination was found to be negligibly small even in the Pt/YIG structure.",1211.0139v2
+2013-01-15,Spin-Hall Magnetoresistance in Platinum on Yttrium Iron Garnet: Dependence on platinum thickness and in-plane/out-of-plane magnetization,"The occurrence of Spin-Hall Magnetoresistance (SMR) in platinum (Pt) on top
+of yttrium iron garnet (YIG) has been investigated, for both in-plane and
+out-of-plane applied magnetic fields and for different Pt thicknesses [3, 4, 8
+and 35nm]. Our experiments show that the SMR signal directly depends on the
+in-plane and out-of-plane magnetization directions of the YIG. This confirms
+the theoretical description, where the SMR occurs due to the interplay of
+spin-orbit interaction in the Pt and spin-mixing at the YIG/Pt interface.
+Additionally, the sensitivity of the SMR and spin pumping signals on the YIG/Pt
+interface conditions is shown by comparing two different deposition techniques
+(e-beam evaporation and dc sputtering).",1301.3266v2
+2013-09-19,Tuning Magnetotransport in PdPt/Y3Fe5O12: Effects of magnetic proximity and spin orbital coupling,"Anisotropic magnetoresistance (AMR) ratio and anomalous Hall conductivity
+(AHC) in PdPt/Y$_3$Fe$_5$O$_{12}$ (YIG) system are tuned significantly by spin
+orbital coupling strength $\xi$ through varying the Pt concentration. For both
+Pt/YIG and Pd/YIG, the maximal AMR ratio is located at temperatures for the
+maximal susceptibility of paramagnetic Pt and Pd metals. The AHC and ordinary
+Hall effect both change the sign with temperature for Pt-rich system and vice
+versa for Pd-rich system. The present results ambiguously evidence the spin
+polarization of Pt and Pd atoms in contact with YIG layers. The global
+curvature near the Fermi surface is suggested to change with the Pt
+concentration and temperature.",1309.4841v2
+2013-11-19,Observation of the spin Peltier effect,"We report the observation of the spin Peltier effect (SPE) in the
+ferrimagnetic insulator Yttrium Iron Garnet (YIG), i.e. a heat current
+generated by a spin current flowing through a Platinum (Pt)|YIG interface. The
+effect can be explained by the spin torque that transforms the spin current in
+the Pt into a magnon current in the YIG. Via magnon-phonon interactions the
+magnetic fluctuations modulate the phonon temperature that is detected by a
+thermopile close to the interface. By finite-element modelling we verify the
+reciprocity between the spin Peltier and spin Seebeck effect. The observed
+strong coupling between thermal magnons and phonons in YIG is attractive for
+nanoscale cooling techniques.",1311.4772v1
+2014-04-08,Modulation of pure spin currents with a ferromagnetic insulator,"We propose and demonstrate spin manipulation by magnetically controlled
+modulation of pure spin currents in cobalt/copper lateral spin valves,
+fabricated on top of the magnetic insulator Y$_3$Fe$_5$O$_{12}$ (YIG). The
+direction of the YIG magnetization can be controlled by a small magnetic field.
+We observe a clear modulation of the non-local resistance as a function of the
+orientation of the YIG magnetization with respect to the polarization of the
+spin current. Such a modulation can only be explained by assuming a finite
+spin-mixing conductance at the Cu/YIG interface, as it follows from the
+solution of the spin-diffusion equation. These results open a new path towards
+the development of spin logics.",1404.2311v2
+2015-03-25,Nature of magnetotransport in metal/insulating-ferromagnet heterostructures: Spin Hall magnetoresistance or magnetic proximity effect,"We study the anomalous Hall-like effect (AHLE) and the effective anisotropic
+magnetoresistance (EAMR) in antiferromagnetic {\gamma} -IrMn3/Y3Fe5O12(YIG) and
+Pt/YIG heterostructures. For {\gamma} -IrMn3/YIG, the EAMR and the AHLE
+resistivity change sign with temperature due to the competition between the
+spin Hall magnetoresistance (SMR) and the magnetic proximity effect (MPE)
+induced by the interfacial antiferromagnetic uncompensated magnetic moment. In
+contrast, for Pt/YIG the AHLE resistivity changes sign with temperature whereas
+no sign change is observed in the EAMR. This is because the MPE and the SMR
+play a dominant role in the AHLE and the EAMR, respectively. As new types of
+galvanomagnetic property, the AHLE and the EAMR have proved vital in
+disentangling the MPE and the SMR in metal/insulating-ferromagnet
+heterostructures.",1503.07388v2
+2015-05-29,Thermal conductance of thin film YIG determined using Bayesian statistics,"Thin film YIG (Y$_3$Fe$_5$O$_{12}$) is a prototypical material for
+experiments on thermally generated pure spin currents and the spin Seebeck
+effect. The 3-omega method is an established technique to measure the
+cross-plane thermal conductance of thin films, but can not be used in YIG/GGG
+(Ga$_3$Gd$_5$O$_{12}$) systems in its standard form. We use two-dimensional
+modeling of heat transport and introduce a technique based on Bayesian
+statistics to evaluate measurement data taken from the 3-omega method. Our
+analysis method allows us to study materials systems that have not been
+accessible with the conventionally used 3-omega analysis. Temperature dependent
+thermal conductance data of thin film YIG are of major importance for
+experiments in the field of spin-caloritronics. Here we show data between room
+temperature and 10 K for films covering a wide thickness range as well as the
+magnetic field effect on the thermal conductance between 10 K and 50 K.",1505.08006v1
+2015-12-30,Non-equilibrium thermodynamics of the spin Seebeck and spin Peltier effects,"We study the problem of magnetization and heat currents and their associated
+thermodynamic forces in a magnetic system by focusing on the magnetization
+transport in ferromagnetic insulators like YIG. The resulting theory is applied
+to the longitudinal spin Seebeck and the spin Peltier effects. By focusing on
+the specific geometry with one YIG layer and one Pt layer, we obtain the
+optimal conditions for generating large magnetization currents into Pt or large
+temperature effects in YIG. The theoretical predictions are compared with
+experiments from the literature permitting to derive the values of the
+thermomagnetic coefficients of YIG: the magnetization diffusion length $l_M
+\sim 0.4 \, \mu$m and the absolute thermomagnetic power coefficient $\epsilon_M
+\sim 10^{-2}$ TK$^{-1}$.",1512.08890v2
+2016-03-02,Enhancement of Thermally Injected Spin Current through an Antiferromagnetic Insulator,"We report large enhancement of thermally injected spin current in normal
+metal (NM)/antiferromagnet(AF)/yttrium iron garnet(YIG), where a thin AF
+insulating layer of NiO or CoO can enhance spin current from YIG to a NM by up
+to a factor of 10. The spin current enhancement in NM/AF/YIG, with a pronounced
+maximum near the N\'eel temperature of the thin AF layer, has been found to
+scale linearly with the spin-mixing conductance at the NM/YIG interface for NM
+= 3d, 4d, and 5d metals. Calculations of spin current enhancement and spin
+mixing conductance are qualitatively consistent with the experimental results.",1603.00931v2
+2016-06-09,"Competing effects at Pt/YIG interfaces: spin Hall magnetoresistance, magnon excitations and magnetic frustration","We study the spin Hall magnetoresistance (SMR) and the magnon spin transport
+(MST) in Pt/Y3Fe5O12(YIG)-based devices with intentionally modified interfaces.
+Our measurements show that the surface treatment of the YIG film results in a
+slight enhancement of the spin-mixing conductance and an extraordinary increase
+in the efficiency of the spin-to-magnon excitations at room temperature. The
+surface of the YIG film develops a surface magnetic frustration at low
+temperatures, causing a sign change of the SMR and a dramatic suppression of
+the MST. Our results evidence that SMR and MST could be used to explore
+magnetic properties of surfaces, including those with complex magnetic
+textures, and stress the critical importance of the non-magnetic/ferromagnetic
+interface properties in the performance of the resulting spintronic devices.",1606.02968v2
+2017-01-10,Temperature dependence of the non-local spin Seebeck effect in YIG/Pt nanostructures,"We study the transport of thermally excited non-equilibrium magnons through
+the ferrimagnetic insulator YIG using two electrically isolated Pt strips as
+injector and detector. The diffusing magnons induce a non- local inverse spin
+Hall voltage in the detector corresponding to the so-called non-local spin
+Seebeck effect (SSE). We measure the non-local SSE as a function of temperature
+and strip separation. In experiments at room temperature we observe a sign
+change of the non-local SSE voltage at a characteristic strip separation d0, in
+agreement with previous investigations. At lower temperatures however, we find
+a strong temperature dependence of d0. This suggests that both the angular
+momentum transfer across the YIG/Pt interface as well as the transport
+mechanism of the magnons in YIG as a function of temperature must be taken into
+account to describe the non-local spin Seebeck effect.",1701.02635v1
+2017-04-25,Probing length-scale separation of thermal and spin currents by nanostructuring YIG,"We have fabricated bulk nanostructured ferrimagnetic materials with different
+grain sizes by sintering ball-milled Y3Fe5O12 (YIG) nanoparticles and measured
+the grain-size dependence of the thermal conductivity and spin Seebeck
+thermopower. The nanostructuring reduces both thermal conductivity and
+thermopower, but the reduction of the latter was found to be considerably
+stronger despite the moderate difference in magnetization, which suggests that
+the length scales of transport of magnons and phonons contributing to the spin
+Seebeck effect are significantly larger than that of phonons carrying thermal
+current. This is consistent with the measurements of high-magnetic-field
+response of the spin Seebeck thermopower and low-temperature thermal
+conductivity, where the quenching of magnons seen in single-crystalline YIG was
+not observed in nanostructured YIG due to scattering of long-range low
+frequency magnons.",1704.07568v1
+2017-09-12,Direct observation of magnon-phonon coupling in yttrium iron garnet,"The magnetic insulator yttrium iron garnet (YIG) with a ferrimagnetic
+transition temperature of $\sim$560 K has been widely used in microwave and
+spintronic devices. Anomalous features in the spin Seeback effect (SSE)
+voltages have been observed in Pt/YIG and attributed to the magnon-phonon
+coupling. Here we use inelastic neutron scattering to map out low-energy spin
+waves and acoustic phonons of YIG at 100 K as a function of increasing magnetic
+field. By comparing the zero and 9.1 T data, we find that instead of splitting
+and opening up gaps at the spin wave and acoustic phonon dispersion
+intersecting points, magnon-phonon coupling in YIG enhances the hybridized
+scattering intensity. These results are different from expectations of
+conventional spin-lattice coupling, calling for new paradigms to understand the
+scattering process of magnon-phonon interactions and the resulting
+magnon-polarons.",1709.03940v1
+2017-11-27,"Magnetic properties, spin waves and interaction between spin excitations and 2D electrons in interface layer in Y3Fe5O12 / AlOx / GaAs-heterostructures","We describe synthesis of submicron Y3Fe5O12 (YIG) films sputtered on
+GaAs-based substrates and present results of the investigation of ferromagnetic
+resonance (FMR), spin wave propagation and interaction between spin excitations
+and 2D electrons in interface layer in YIG / AlOx / GaAs-heterostructures. It
+is found that the contribution of the relaxation process to the FMR linewidth
+is about 2 % of the linewidth \Delta H. At the same time, for all samples FMR
+linewidths are high. Sputtered YIG films have magnetic inhomogeneity, which
+gives the main contribution to the FMR linewidth. Transistor structures with
+two-dimensional electron gas (2DEG) channels in AlOx / GaAs interface governed
+by YIG-film spin excitations are designed. An effective influence of spin
+excitations on the current flowing through the GaAs 2DEG channel is observed.
+Light illumination results in essential changes in the FMR spectrum. It is
+found that an increase of the 2DEG current leads to an inverse effect, which
+represents essential changes in the FMR spectrum.",1711.09814v1
+2018-04-30,Single-Nitrogen-vacancy-center quantum memory for a superconducting flux qubit mediated by a ferromagnet,"We propose a quantum memory scheme to transfer and store the quantum state of
+a superconducting flux qubit (FQ) into the electron spin of a single
+nitrogen-vacancy (NV) center in diamond via yttrium iron garnet (YIG), a
+ferromagnet. Unlike an ensemble of NV centers, the YIG moderator can enhance
+the effective FQ-NV-center coupling strength without introducing additional
+appreciable decoherence. We derive the effective interaction between the FQ and
+the NV center by tracing out the degrees of freedom of the collective mode of
+the YIG spins. We demonstrate the transfer, storage, and retrieval procedures,
+taking into account the effects of spontaneous decay and pure dephasing. Using
+realistic experimental parameters for the FQ, NV center and YIG, we find that a
+combined transfer, storage, and retrieval fidelity higher than 0.9, with a long
+storage time of 10 ms, can be achieved. This hybrid system not only acts as a
+promising quantum memory, but also provides an example of enhanced coupling
+between various systems through collective degrees of freedom.",1804.11231v1
+2019-02-12,Characterization of spin wave propagation in (111) YIG thin films with large anisotropy,"We report on long-range spin wave (SW) propagation in nanometer-thick yttrium
+iron garnet (YIG) film with an ultralow Gilbert damping. The knowledge of a
+wavenumber value $|\vec{k}|$ is essential for designing SW devices. Although
+determining the wavenumber $|\vec{k}|$ in experiments like Brillouin light
+scattering spectroscopy is straightforward, quantifying the wavenumber in
+all-electrical experiments has not been widely commented upon so far. We
+analyze magnetostatic spin wave (SW) propagation in YIG films in order to
+determine the SW wavenumber $|\vec{k}|$ excited by the coplanar waveguide. We
+show that it is crucial to consider the influence of magnetic anisotropy fields
+present in YIG thin films for precise determination of SW wavenumber. With the
+proposed methods we find that experimentally derived values of $|\vec{k}|$ are
+in perfect agreement with that obtained from electromagnetic simulation only if
+anisotropy fields are included.",1902.04608v1
+2019-04-09,Ferromagnetic Resonance Studies of Strain tuned Bi:YIG Films,"Bismuth-doped Yttrium iron garnet (Bi:YIG) thin films known for large
+Magneto-optical activity with low losses still needs to get probed for its
+magnetization dynamics. We demonstrate a controlled tuning of
+magnetocrystalline anisotropy in Bi-doped Y_3 Fe_5 O_12 (Bi:YIG) films of high
+crystalline quality using growth induced epitaxial strain on [111]-oriented
+Gd_3 Ga_5 O_12 (GGG) substrate. We optimize a growth protocol to get thick
+highly-strained epitaxial films showing large magneto-crystalline anisotropy,
+compare to thin films prepared using a different protocol. Ferromagnetic
+resonance measurements establish a linear dependence of the out-of-plane
+uniaxial anisotropy on the strain induced rhombohedral distortion of Bi:YIG
+lattice. Interestingly, the enhancement in the magnetoelastic constant due to
+an optimum substitution of Bi^(3+) ions with strong spin orbit coupling does
+not strongly affect the precessional damping (~2x10^(-3) ). Large
+magneto-optical activity, reasonably low damping, large magnetocrystalline
+anisotropy and large magnetoelastic coupling in BiYIG are the properties that
+may help BiYIG emerge as a possible material for photo-magnonics and other
+spintronics applications.",1904.04800v2
+2019-04-23,Current-induced switching of YIG/Pt bilayers with in-plane magnetization due to Oersted fields,"We report on the switching of the in-plane magnetization of thin yttrium iron
+garnet (YIG)/Pt bilayers induced by an electrical current. The switching is
+either field-induced and assisted by a dc current, or current-induced and
+assisted by a static magnetic field. The reversal of the magnetization occurs
+at a current density as low as $10^5$~A/cm$^{2}$ and magnetic fields of $\sim
+40$~$\mu$T, two orders of magnitude smaller than in ferromagnetic metals,
+consistently with the weak uniaxial anisotropy of the YIG layers. We use the
+transverse component of the spin Hall magnetoresistance to sense the magnetic
+orientation of YIG while sweeping the current. Our measurements and simulations
+reveal that the current-induced effective field responsible for switching is
+due to the Oersted field generated by the current flowing in the Pt layer
+rather than by spin-orbit torques, and that the switching efficiency is
+influenced by pinning of the magnetic domains.",1904.10517v1
+2019-09-09,Modulation of magnon spin transport in a magnetic gate transistor,"We demonstrate a modulation of up to 18% in the magnon spin transport in a
+magnetic insulator (Y$_{3}$Fe$_{5}$O$_{12}$, YIG) using a common ferromagnetic
+metal (permalloy, Py) as a magnetic control gate. A Py electrode, placed
+between two Pt injector and detector electrodes, acts as a magnetic gate in our
+prototypical magnon transistor device. By manipulating the magnetization
+direction of Py with respect to that of YIG, the transmission of magnons
+through the Py|YIG interface can be controlled, resulting in a modulation of
+the non-equilibrium magnon density in the YIG channel between the Pt injector
+and detector electrodes. This study opens up the possibility of using the
+magnetic gating effect for magnon-based spin logic applications.",1909.03775v1
+2020-01-15,Yttrium Iron Garnet Thickness Influence on the Spin Pumping in the Bulk Acoustic Wave Resonator,"The features of phonon-magnon interconversion in acoustic resonator determine
+the efficiency of spin pumping from YIG into Pt that may be detected
+electrically through the inverse spin Hall effect (ISHE). Based on the methods
+developed in previous works for calculating resonator structures with a
+piezoelectric (ZnO) and a magnetoelastic layer in contact with the heavy metal
+(YIG/Pt), we present the results of numerical calculations of YIG film
+thickness influence on acoustically driven spin waves. We obtain some YIG film
+thickness regions with various behavior of dc ISHE voltage $U_{ISHE}$. At
+micron and submicron thicknesses, the higher spin wave resonance (SWR) modes
+(both even and odd) can be generated with efficiency comparable and even
+exceeding that of the main mode. The absolute maximum of $U_{ISHE}$ is achieved
+at the thickness about $s_1 \approx 208$ nm under the excitation of the first
+SWR.",2001.05385v1
+2020-02-28,Spin Hall magnetoresistance in Pt/YIG bilayers via varying magnon excitation,"Spin Hall magnetoresistance (SMR) and magnon excitation magnetoresistance
+(MMR) that all generate via the spin Hall effect and inverse spin Hall effect
+in a nonmagnetic material are always related to each other. However, the
+influence of magnon excitation for SMR is often overlooked due to the
+negligible MMR. Here, we investigate the SMR in Pt/Y3Fe5O12 (YIG) bilayers from
+5 to 300K, in which the YIG are treated after Ar+-ion milling. The SMR in the
+treated device is smaller than in the non-treated. According to theoretical
+simulation, we attribute this phenomenon to the reduction of the interfacial
+spin-mixing conductance at the treated Pt/YIG interface induced by the magnon
+suppression. Our experimental results point out that the SMR and the MMR are
+inter-connected, and the former could be modulated via magnon excitation. Our
+findings provide a new approach for separating and clarifying the underlying
+mechanisms.",2002.12550v1
+2021-01-08,Compact tunable YIG-based RF resonators,"We report on the design, fabrication, and characterization of compact tunable
+yttrium iron garnet (YIG) based RF resonators based on $\mu$m-sized spin-wave
+cavities. Inductive antennas with both ladder and meander configurations were
+used as transducers between spin waves and RF signals. The excitation of
+ferromagnetic resonance and standing spin waves in the YIG cavities led to
+sharp resonances with quality factors up to 350. The observed spectra were in
+excellent agreement with a model based on the spin-wave dispersion relations in
+YIG, showing a high magnetic field tunability of about 29 MHz/mT.",2101.02909v4
+2022-11-27,Entangled atomic ensemble and an yttrium-iron-garnet sphere in coupled microwave cavities,"We present a scheme to generate distant bipartite and tripartite entanglement
+between an atomic ensemble and an yttrium iron garnet (YIG) sphere in coupled
+microwave cavities. We consider an atomic ensemble in a single-mode microwave
+cavity which is coupled with a second single-mode cavity having a YIG sphere.
+Our system, therefore, has five excitation modes namely cavity-1 photons,
+atomic ensemble, cavity-2 photons, a magnon and a phonon mode in the YIG
+sphere. We show that significant bipartite entanglement exists between
+indirectly coupled subsystems in the cavities, which is robust against
+temperature. Moreover, we present suitable parameters for a significant
+tripartite entanglement of ensemble, magnon, and phonon modes. We also
+demonstrate the existence of tripartite entanglement between magnon and phonon
+modes of the YIG sphere with indirectly coupled cavity photons. Interestingly,
+this distant tripartite entanglement is of the same order as previously found
+for a single-cavity system. We show that cavity-cavity coupling strength
+affects both the degree and transfer of quantum entanglement between various
+subsystems. Therefore, an appropriate cavity-cavity coupling optimizes the
+distant entanglement by increasing the entanglement strength and its robustness
+against temperature.",2211.14914v2
+2023-06-05,Spin Hall magnetoresistance in Pt/Y$_{3}$Fe$_{5}$O$_{12}$ bilayers grown on Si and Gd$_{3}$Ga$_{5}$O$_{12}$ substrates,"We study spin Hall magnetoresistance (SMR) in Pt/ferrimagnetic insulator
+Y$_{3}$Fe$_{5}$O$_{12}$ (YIG) bilayers by focusing on crystallinity,
+magnetization, and interface roughness by controlling post-annealing
+temperatures. The SMR in the Pt/YIG grown on Si substrate is comparable to that
+grown on widely used Gd$_{3}$Ga$_{5}$O$_{12}$ substrate, indicating that the
+large SMR can be achieved irrespective to the crystallinity. We deduced the
+spin mixing conductance from the Pt thickness dependence of the SMR to find the
+high interface quality of the optimized Pt/YIG grown on Si in terms of spin
+current. We also clarified that the SMR correlates well with the magnetization,
+the interface roughness, and carrier density. These findings highlight that
+optimizing YIG properties is a key to control of magnetization by spin current,
+leading to the development of low power consumption spintronic device based on
+the magnetic insulator.",2306.02575v1
+2024-01-17,Giant Enhancement of Vacuum Friction in Spinning YIG Nanospheres,"Experimental observations of vacuum radiation and vacuum frictional torque
+are challenging due to their vanishingly small effects in practical systems.
+For example, a rotating nanosphere in free space slows down due to friction
+from vacuum fluctuations with a stopping time around the age of the universe.
+Here, we show that a spinning yttrium iron garnet (YIG) nanosphere near
+aluminum or YIG slabs exhibits vacuum radiation eight orders of magnitude
+larger than other metallic or dielectric spinning nanospheres. We achieve this
+giant enhancement by exploiting the large near-field magnetic local density of
+states in YIG systems, which occurs in the low-frequency GHz regime comparable
+to the rotation frequency. Furthermore, we propose a realistic experimental
+setup for observing the effects of this large vacuum radiation and frictional
+torque under experimentally accessible conditions.",2401.09563v1
+2024-03-05,Generation of gigahertz frequency surface acoustic waves in YIG/ZnO heterostructures,"We study surface acoustic waves (SAWs) in yttrium iron garnet (YIG)/zinc
+oxide (ZnO) heterostructures, comparing the results of a computationally
+lightweight analytical model with time-resolved micro-focused Brillouin light
+scattering data. Interdigital transducers (IDTs), with operational frequencies
+in the gigahertz regime, were fabricated on 50 and 100nm thin films of YIG
+prior to sputter deposition of 830nm and 890nm films of piezoelectric ZnO. We
+find good agreement between our analytical model and micro-focused Brillouin
+light scattering data of the IDT frequency response and SAW group velocity,
+with clear differentiation between the Rayleigh and Sezawa-like modes. This
+work paves the way for the study of SAW-spin wave (SW) interactions in low SW
+damping YIG, with the possibility of a method for future energy-efficient SW
+excitation.",2403.03006v1
+2024-02-19,Magnetic anisotropy and GGG substrate stray field in YIG films down to millikelvin temperatures,"Quantum magnonics investigates the quantum-mechanical properties of magnons
+such as quantum coherence or entanglement for solid-state quantum information
+technologies at the nanoscale. The most promising material for quantum
+magnonics is the ferrimagnetic yttrium iron garnet (YIG), which hosts magnons
+with the longest lifetimes. YIG films of the highest quality are grown on a
+paramagnetic gadolinium gallium garnet (GGG) substrate. The literature has
+reported that ferromagnetic resonance (FMR) frequencies of YIG/GGG decrease at
+temperatures below 50 K despite the increase in YIG magnetization. We
+investigated a 97 nm-thick YIG film grown on 500 $\mathrm{\mu}$m-thick GGG
+substrate through a series of experiments conducted at temperatures as low as
+30 mK, and using both analytical and numerical methods. Our findings suggest
+that the primary factor contributing to the FMR frequency shift is the stray
+magnetic field created by the partially magnetized GGG substrate. This stray
+field is antiparallel to the applied external field and is highly
+inhomogeneous, reaching up to 40 mT in the center of the sample. At
+temperatures below 500 mK, the GGG field exhibits a saturation that cannot be
+described by the standard Brillouin function for a paramagnet. Including the
+calculated GGG field in the analysis of the FMR frequency versus temperature
+dependence allowed the determination of the cubic and uniaxial anisotropies. We
+find that the total anisotropy increases more than three times with the
+decrease in temperature down to 2 K. Our findings enable accurate predictions
+of the YIG/GGG magnetic systems behavior at low and ultra-low millikelvin
+temperatures, crucial for developing quantum magnonic devices.",2402.12112v1
+2015-12-02,Thermodynamics of the heat currents in the longitudinal spin Seebeck and spin Peltier effects,"We employ the non-equilibrium thermodynamics of currents and forces to
+describe the heat transport caused by a spin current in a Pt/YIG bilayer. By
+starting from the constitutive equations of the magnetization currents in both
+Pt and YIG, we derive the magnetization potentials and currents. We apply the
+theory to the spin Peltier experiments in which a spin current, generated by
+the spin Hall effect in Pt, is injected into YIG. We find that efficient
+injection is obtained when: i) the thickness of each layer is larger than its
+diffusion length: $t_{Pt} > l_{Pt}$ and $t_{YIG} > l_{YIG}$ and ii) the ratio
+$(l_{Pt}/\tau_{Pt})/(l_{YIG}/\tau_{YIG})$ is small, where $\tau_i$ is the time
+constant of the intrinsic damping ($i=Pt, YIG$). We finally derive the
+temperature profile in adiabatic conditions. The scale of the effect is given
+by the parameter $\Delta T_{SH}$ which is proportional to the electric current
+in Pt. Using known parameters for Pt and YIG we estimate $\Delta T_{SH}/j_e = 4
+\cdot 10^{-13}$ K A$^{-1}$m$^2$. This value is of the same order of magnitude
+of the spin Peltier experiments.",1512.00644v2
+2016-12-22,Imaging Magnetization Structure and Dynamics in Ultrathin YIG/Pt Bilayers with High Sensitivity Using the Time-Resolved Longitudinal Spin Seebeck Effect,"We demonstrate an instrument for time-resolved magnetic imaging that is
+highly sensitive to the in-plane magnetization state and dynamics of thin-film
+bilayers of yttrium iron garnet (Y3Fe5O12,YIG)/Pt: the time-resolved
+longitudinal spin Seebeck (TRLSSE) effect microscope. We detect the local,
+in-plane magnetic orientation within the YIG by focusing a picosecond laser to
+generate thermally-driven spin current from the YIG into the Pt by the spin
+Seebeck effect, and then use the inverse spin Hall effect in the Pt to
+transduce this spin current to an output voltage. To establish the time
+resolution of TRLSSE, we show that pulsed optical heating of patterned YIG (20
+nm)/Pt(6 nm)/Ru (2 nm) wires generates a magnetization-dependent voltage pulse
+of less than 100 ps. We demonstrate TRLSSE microscopy to image both static
+magnetic structure and gigahertz-frequency magnetic resonance dynamics with
+sub-micron spatial resolution and a sensitivity to magnetic orientation below
+0.3$^{\circ}/\sqrt{\text{Hz}}$ in ultrathin YIG.",1612.07610v2
+2017-03-26,Unexpected structural and magnetic depth dependence of YIG thin films,"We report measurements on yttrium iron garnet (YIG) thin films grown on both
+gadolinium gallium garnet (GGG) and yttrium aluminium garnet (YAG) substrates,
+with and without thin Pt top layers. We provide three principal results: the
+observation of an interfacial region at the Pt/YIG interface, we place a limit
+on the induced magnetism of the Pt layer and confirm the existence of an
+interfacial layer at the GGG/YIG interface. Polarised neutron reflectometry
+(PNR) was used to give depth dependence of both the structure and magnetism of
+these structures. We find that a thin film of YIG on GGG is best described by
+three distinct layers: an interfacial layer near the GGG, around 5 nm thick and
+non-magnetic, a magnetic bulk phase, and a non-magnetic and compositionally
+distinct thin layer near the surface. We theorise that the bottom layer, which
+is independent of the film thickness, is caused by Gd diffusion. The top layer
+is likely to be extremely important in inverse spin Hall effect measurements,
+and is most likely Y2O3 or very similar. Magnetic sensitivity in the PNR to any
+induced moment in the Pt is increased by the existence of the Y2O3 layer; any
+moment is found to be less than 0.02 uB/atom.",1703.08752v1
+2017-11-20,Temperature dependent relaxation of dipole-exchange magnons in yttrium iron garnet films,"Low energy consumption enabled by charge-free information transport, which is
+free from ohmic heating, and the ability to process phase-encoded data by
+nanometer-sized interference devices at GHz and THz frequencies are just a few
+benefits of spin-wave-based technologies. Moreover, when approaching cryogenic
+temperatures, quantum phenomena in spin-wave systems pave the path towards
+quantum information processing. In view of these applications, the lifetime of
+magnons$-$spin-wave quanta$-$is of high relevance for the fields of magnonics,
+magnon spintronics and quantum computing. Here, the relaxation behavior of
+parametrically excited magnons having wavenumbers from zero up to $6\cdot 10^5
+\mathrm{rad~cm}^{-1}$ was experimentally investigated in the temperature range
+from 20 K to 340 K in single crystal yttrium iron garnet (YIG) films
+epitaxially grown on gallium gadolinium garnet (GGG) substrates as well as in a
+bulk YIG crystal$-$the magnonic materials featuring the lowest magnetic damping
+known so far. As opposed to the bulk YIG crystal in YIG films we have found a
+significant increase in the magnon relaxation rate below 150 K$-$up to 10.5
+times the reference value at 340 K$-$in the entire range of probed wavenumbers.
+This increase is associated with rare-earth impurities contaminating the YIG
+samples with a slight contribution caused by coupling of spin waves to the spin
+system of the paramagnetic GGG substrate at the lowest temperatures.",1711.07517v1
+2018-02-26,Spin Seebeck effect and ballistic transport of quasi-acoustic magnons in room-temperature yttrium iron garnet films,"We studied the transient behavior of the spin current generated by the
+longitudinal spin Seebeck effect (LSSE) in a set of platinum-coated yttrium
+iron garnet (YIG) films of different thicknesses. The LSSE was induced by means
+of pulsed microwave heating of the Pt layer and the spin currents were measured
+electrically using the inverse spin Hall effect in the same layer. We
+demonstrate that the time evolution of the LSSE is determined by the evolution
+of the thermal gradient triggering the flux of thermal magnons in the vicinity
+of the YIG/Pt interface. These magnons move ballistically within the YIG film
+with a constant group velocity, while their number decays exponentially within
+an effective propagation length. The ballistic flight of the magnons with
+energies above 20K is a result of their almost linear dispersion law, similar
+to that of acoustic phonons. By fitting the time-dependent LSSE signal for
+different film thicknesses varying by almost an order of magnitude, we found
+that the effective propagation length is practically independent of the YIG
+film thickness. We consider this fact as strong support of a ballistic
+transport scenario - the ballistic propagation of quasi-acoustic magnons in
+room temperature YIG.",1802.09593v1
+2019-06-28,Spin transport in an insulating ferrimagnetic-antiferromagnetic-ferrimagnetic trilayer as a function of temperature,"We present a study of the transport properties of thermally generated spin
+currents in an insulating ferrimagnetic-antiferromagnetic-ferrimagnetic
+trilayer over a wide range of temperature. Spin currents generated by the spin
+Seebeck effect (SSE) in a yttrium iron garnet (YIG) YIG/NiO/YIG trilayer on a
+gadolinium gallium garnet (GGG) substrate were detected using the inverse spin
+Hall effect in Pt. By studying samples with different NiO thicknesses, the NiO
+spin diffusion length was determined to be 4.2 nm at room temperature.
+Interestingly, below 30 K, the inverse spin Hall signals are associated with
+the GGG substrate. The field dependence of the signal follows a Brillouin
+function for a S=7/2 spin ($\mathrm{Gd^{3+}}$) at low temperature. Sharp
+changes in the SSE signal at low fields are due to switching of the YIG
+magnetization. A broad peak in the SSE response was observed around 100 K,
+which we associate with an increase in the spin-diffusion length in YIG. These
+observations are important in understanding the generation and transport
+properties of spin currents through magnetic insulators and the role of a
+paramagnetic substrate in spin current generation.",1906.12288v1
+2019-11-21,Low damping and microstructural perfection of sub-40nm-thin yttrium iron garnet films grown by liquid phase epitaxy,"The field of magnon spintronics is experiencing an increasing interest in the
+development of solutions for spin-wave-based data transport and processing
+technologies that are complementary or alternative to modern CMOS
+architectures. Nanometer-thin yttrium iron garnet (YIG) films have been the
+gold standard for insulator-based spintronics to date, but a potential process
+technology that can deliver perfect, homogeneous large-diameter films is still
+lacking. We report that liquid phase epitaxy (LPE) enables the deposition of
+nanometer-thin YIG films with low ferromagnetic resonance losses and
+consistently high magnetic quality down to a thickness of 20 nm. The obtained
+epitaxial films are characterized by an ideal stoichiometry and perfect film
+lattices, which show neither significant compositional strain nor geometric
+mosaicity, but sharp interfaces. Their magneto-static and dynamic behavior is
+similar to that of single crystalline bulk YIG. We found, that the Gilbert
+damping coefficient alpha is independent of the film thickness and close to 1 x
+10-4, and that together with an inhomogeneous peak-to-peak linewidth broadening
+of delta H0|| = 0.4 G, these values are among the lowest ever reported for YIG
+films with a thickness smaller than 40 nm. These results suggest, that
+nanometer-thin LPE films can be used to fabricate nano- and micro-scaled
+circuits with the required quality for magnonic devices. The LPE technique is
+easily scalable to YIG sample diameters of several inches.",1911.09400v1
+2021-09-10,Electrical spectroscopy of the spin-wave dispersion and bistability in gallium-doped yttrium iron garnet,"Yttrium iron garnet (YIG) is a magnetic insulator with record-low damping,
+allowing spin-wave transport over macroscopic distances. Doping YIG with
+gallium ions greatly reduces the demagnetizing field and introduces a
+perpendicular magnetic anisotropy, which leads to an isotropic spin-wave
+dispersion that facilitates spin-wave optics and spin-wave steering. Here, we
+characterize the dispersion of a gallium-doped YIG (Ga:YIG) thin film using
+electrical spectroscopy. We determine the magnetic anisotropy parameters from
+the ferromagnetic resonance frequency and use propagating spin wave
+spectroscopy in the Damon-Eshbach configuration to detect the small spin-wave
+magnetic fields of this ultrathin weak magnet over a wide range of wavevectors,
+enabling the extraction of the exchange constant $\alpha=1.3(2)\times10^{-12}$
+J/m. The frequencies of the spin waves shift with increasing drive power, which
+eventually leads to the foldover of the spin-wave modes. Our results shed light
+on isotropic spin-wave transport in Ga:YIG and highlight the potential of
+electrical spectroscopy to map out the dispersion and bistability of
+propagating spin waves in magnets with a low saturation magnetization.",2109.05045v1
+2022-03-30,Tunable magnetically induced transparency spectra in magnon-magnon coupled Y3Fe5O12/permalloy bilayers,"Hybrid magnonic systems host a variety of characteristic quantum phenomena
+such as the magnetically-induced transparency (MIT) and Purcell effect, which
+are considered useful for future coherent quantum information processing. In
+this work, we experimentally demonstrate a tunable MIT effect in the
+Y3Fe5O12(YIG)/Permalloy(Py) magnon-magnon coupled system via changing the
+magnetic field orientations. By probing the magneto-optic effects of Py and
+YIG, we identify clear features of MIT spectra induced by the mode
+hybridization between the uniform mode of Py and the perpendicular standing
+spin-wave modes of YIG. By changing the external magnetic field orientations,
+we observe a tunable coupling strength between the YIG's spin-wave modes and
+the Py's uniform mode, upon the application of an out-of-plane magnetic field.
+This observation is theoretically interpreted by a geometrical consideration of
+the Py and YIG magnetization under the oblique magnetic field even at a
+constant interfacial exchange coupling. Our findings show high promise for
+investigating tunable coherent phenomena with hybrid magnonic platforms.",2203.16303v1
+2023-01-16,Crystal orientation dependent spin pumping in Bi0.1Y2.9Fe5O12/Pt interface,"Ferromagnetic resonance (FMR) based spin pumping is a versatile tool to
+quantify the spin mixing conductance and spin to charge conversion (S2CC)
+efficiency of ferromagnet/normal metal (FM/NM) heterostructure. The spin mixing
+conductance of FM/NM interface can also be tuned by the crystal orientation
+symmetry of epitaxial FM. In this work, we study the S2CC in epitaxial Bismuth
+substituted Yttrium Iron Garnet (Bi0.1Y2.9Fe5O12) thin films Bi-YIG (100 nm)
+interfaced with heavy metal platinum (Pt (8 nm)) deposited by pulsed laser
+deposition process on different crystal orientation Gd3Ga5O12 (GGG) substrates
+i.e. [100] and [111]. The crystal structure and surface roughness characterized
+by X-Ray diffraction and atomic force microscopy measurements establish
+epitaxial Bi-YIG[100], Bi-YIG[111] orientations and atomically flat surfaces
+respectively. The S2CC quantification has been realized by two complimentary
+techniques, (i) FMR-based spin pumping and inverse spin Hall effect (ISHE) at
+GHz frequency and (ii) temperature dependent spin Seebeck measurements.
+FMR-ISHE results demonstrate that the [111] oriented Bi-YIG/Pt sample shows
+significantly higher values of spin mixing conductance ((2.31+-0.23)x10^18
+m^-2) and spin Hall angle (0.01+-0.001) as compared to the [100] oriented
+Bi-YIG/Pt. A longitudinal spin Seebeck measurement reveals that the [111]
+oriented sample has higher spin Seebeck coefficient (106.40+-10 nV mm-1 K-1).
+This anisotropic nature of spin mixing conductance and spin Seebeck coefficient
+in [111] and [100] orientation has been discussed using the magnetic
+environment elongation along the surface normal or parallel to the growth
+direction. Our results aid in understanding the role of crystal orientation
+symmetry in S2CC based spintronics devices.",2301.06477v1
+2020-02-02,A millimeter-wave Bell Test using a ferrite parametric amplifier and a homodyne interferometer,"A combined ferrite parametric amplifier and millimeter-wave homodyne
+interferometer are proposed as an ambient temperature Bell Test. It is shown
+that the non-linear magnetic susceptibility of the yttrium iron garnet (YIG)
+ferrite, on account of its narrow line-width Larmor precessional resonance,
+make it an ideal material for the creation of entangled photons. These can be
+measured using a homodyne interferometer, as the much larger number of
+thermally generated photons associated with ambient temperature emission can be
+screened out. The proposed architecture may enable YIG quantum technology-based
+sensors to be developed, mimicking in the millimeter-wave band the large number
+of quantum optical experiments in the near-infrared and visible regions which
+had been made possible by use of the nonlinear beta barium borate
+ferroelectric, an analogue of YIG. It is illustrated here how the YIG
+parametric amplifier can reproduce quantum optical Type I and Type II wave
+interactions, which can be used to create entangled photons in the
+millimeter-wave band. It is estimated that when half a cubic centimeter of YIG
+crystal is placed in a magnetic field of a few Tesla and pumped with 5 Watts of
+millimeter-wave radiation, approximately 0.5x10^12 entangled millimeter-wave
+photon pairs per second are generated by the spin-wave interaction. This means
+an integration time of only a few tens of seconds is needed for a successful
+Bell Test. A successful demonstration of this will lead to novel architectures
+of entanglement-based quantum technology room temperature sensors,
+re-envisioning YIG as a modern quantum material.",2002.00439v3
+2024-02-01,Exploring inverse orbital Hall and orbital Rashba effects: unveiling the oxidation states of the Cu surface,"In this work, employing spin-pumping techniques driven by both ferromagnetic
+resonance (SP-FMR) and longitudinal spin Seebeck effect (LSSE) to manipulate
+and direct observe orbital currents, we investigated the volume conversion of
+spin-orbital currents into charge-current in YIG(100nm)/Pt(2nm)/NM2 structures,
+where NM2 represents Ti or Ru. While the YIG/Ti bilayer displayed a negligible
+SP-FMR signal, the YIG/Pt/Ti structure exhibited a significantly stronger
+signal attributed to the orbital Hall effect of Ti. Substituting the Ti layer
+with Ru revealed a similar phenomenon, wherein the effect is ascribed to the
+combined action of both spin and orbital Hall effects. Furthermore, we measured
+the SP-FMR signal in the YIG/Pt(2)/Ru(6)/Ti(6) and YIG/Pt(2)/Ti(6)/Ru(6)
+heterostructures by just altering the stack order of Ti and Ru layers, where
+the peak value of the spin pumping signal is larger for the first sample. To
+verify the influence on the oxidation of Ti and Ru films, we studied a series
+of thin films subjected to controlled and natural oxidation. As Cu and CuOx is
+a system that is already known to be highly influenced by oxidation, this metal
+was chosen to carry out this study. We investigated these samples using SP-FMR
+in YIG/Pt(2)/CuOx(tCu) and X-ray absorption spectroscopy and concluded that
+samples with natural oxidation of Cu exhibit more significant results than
+those when the CuOx is obtained by reactive sputtering. In particular, samples
+where the Cu layer is naturally oxidized exhibit a Cu2O-rich phase. Our
+findings help to elucidate the mechanisms underlying the inverse orbital Hall
+and inverse orbital Rashba-Edelstein-like effects. These insights indeed
+contribute to the advancement of devices that rely on orbital-charge
+conversion.",2402.00297v1
+2002-01-23,Mechanical detection of FMR spectrum in a normally magnetized YIG disk,"The ferromagnetic resonance spectrum of a normally magnetized YIG disk, with
+thickness of 4.75$\mu$m and radius of 80$\mu$m, is measured at room temperature
+both by magnetic resonance force microscopy and by standard detection of the
+microwave susceptibility. The comparison indicates that MRFM represents one of
+the most potent means of obtaining the \emph{complete} FMR spectra of
+micron-size samples. In the weak coupling regime, the measured data can be
+quantitatively understood within the framework of the Damon and Eshbach model.",0201409v1
+2007-11-10,Stability of Bose Einstein condensates of hot magnons in YIG,"We investigate the stability of the recently discovered room temperature
+Bose-Einstein condensate (BEC) of magnons in Ytrrium Iron Garnet (YIG) films.
+We show that magnon-magnon interactions depend strongly on the external field
+orientation, and that the BEC in current experiments is actually metastable -
+it only survives because of finite size effects, and because the BEC density is
+very low. On the other hand a strong field applied perpendicular to the sample
+plane leads to a repulsive magnon-magnon interaction; we predict that a
+high-density magnon BEC can then be formed in this perpendicular field
+geometry.",0711.1574v1
+2014-12-03,Proximity-induced ferromagnetism in graphene revealed by anomalous Hall effect,"We demonstrate the anomalous Hall effect (AHE) in single-layer graphene
+exchange-coupled to an atomically flat yttrium iron garnet (YIG) ferromagnetic
+thin film. The anomalous Hall conductance has magnitude of ~0.09(2e2/h) at low
+temperatures and is measurable up to ~ 300 K. Our observations indicate not
+only proximity-induced ferromagnetism in graphene/YIG with large exchange
+interaction, but also enhanced spin-orbit coupling which is believed to be
+inherently weak in ideal graphene. The proximity-induced ferromagnetic order in
+graphene can lead to novel transport phenomena such as the quantized AHE which
+are potentially useful for spintronics.",1412.1521v1
+2015-03-09,Magnetic spheres in microwave cavities,"We apply Mie scattering theory to study the interaction of magnetic spheres
+with microwaves in cavities beyond the magnetostatic and rotating wave
+approximations. We demonstrate that both strong and ultra-strong coupling can
+be realized for a stand alone magnetic spheres made from yttrium iron garnet
+(YIG), acting as an efficient microwave antenna. The eigenmodes of YIG spheres
+with radii of the order mm's display distinct higher angular momentum character
+that has been observed in experiments.",1503.02419v2
+2017-07-12,Superconductivity Induced by Interfacial Coupling to Magnons,"We consider a thin normal metal sandwiched between two ferromagnetic
+insulators. At the interfaces, the exchange coupling causes electrons within
+the metal to interact with magnons in the insulators. This electron-magnon
+interaction induces electron-electron interactions, which, in turn, can result
+in p-wave superconductivity. In the weak-coupling limit, we solve the gap
+equation numerically and estimate the critical temperature. In YIG-Au-YIG
+trilayers, superconductivity sets in at temperatures somewhere in the interval
+between 1 and 10 K. EuO-Au-EuO trilayers require a lower temperature, in the
+range from 0.01 to 1 K.",1707.03754v1
+2019-10-09,Thermally controlled confinement of spin wave field in a magnonic YIG waveguide,"Methods for detecting spin waves rely on electrodynamical coupling between
+the spin wave dipolar field and an inductive probe. While this coupling is
+usually treated as constant, in this work, we experimentally and theoretically
+show that it is indeed temperature dependent. By measuring the spin wave
+magnetic field as a function of temperature of, and distance to the sample, we
+demonstrate that there is both a longitudinal and transversal confinement of
+the field near the YIG-Air interface. Our results are relevant for spin wave
+detection, in particular in the field of spin wave caloritronics",1910.04304v1
+2020-09-22,From Chaotic Spin Dynamics to Non-collinear Spin Textures in YIG Nano-films by Spin Current Injection,"In this article I report about a numerical investigation of nonlinear spin
+dynamics in a magnetic thin-film, made of Yttrium-Iron-Garnet (YIG). This film
+is exposed to a small in-plane oriented magnetic field, and strong spin
+currents. The rich variety of findings encompass dynamic regimes hosting
+localized, non-propagating solitons, a turbulent chaotic regime, which
+condenses into a quasi-static phase featuring a non-collinear spin texture.
+Eventually, at largest spin current, a homogeneously switched state is
+established.",2009.10628v1
+2022-02-08,Modulation of Spin Seebeck Effect by Hydrogenation,"We demonstrate the modulation of spin Seebeck effect (SSE) by hydrogenation
+in Pd/YIG bilayers. In the presence of 3% hydrogen gas, SSE voltage decreases
+by more than 50% from the magnitude observed in pure Ar gas. The modulation of
+the SSE voltage is reversible, but the recovery of the SSE voltage to the
+prehydrogenation value takes a few days because of a long time constant of
+hydrogen desorption. We also demonstrate that the spin Hall magnetoresistance
+of the identical sample reduces significantly with hydrogen exposure,
+supporting that the observed modulation of spin current signals originates from
+hydrogenation of Pd/YIG.",2202.03774v1
+2023-01-14,Quantum entanglement generation on magnons assisted with microwave cavities coupled to a superconducting qubit,"We present protocols to generate quantum entanglement on nonlocal magnons in
+hybrid systems composed of yttrium iron garnet (YIG) spheres, microwave
+cavities and a superconducting (SC) qubit. In the schemes, the YIGs are coupled
+to respective microwave cavities in resonant way, and the SC qubit is placed at
+the center of the cavities, which interacts with the cavities simultaneously.
+By exchanging the virtual photon, the cavities can indirectly interact in the
+far-detuning regime. Detailed protocols are presented to establish entanglement
+for two, three and arbitrary $N$ magnons with reasonable fidelities.",2301.05820v1
+2014-09-19,Study of strong photon-magnon coupling in a YIG-film split-ring resonant system,"By using the stripline Microwave Vector Network Analyzer Ferromagnetic
+Resonance and Pulsed Inductive Microwave Magnetometry spectroscopy techniques,
+we study a strong coupling regime of magnons to microwave photons in the planar
+geometry of a lithographically formed split-ring resonator (SRR) loaded by a
+single-crystal epitaxial yttrium-iron garnet (YIG) film. Strong anti-crossing
+of the photon modes of SRR and of the magnon modes of the YIG film is observed
+in the applied-magnetic-field resolved measurements. The coupling strength
+extracted from the experimental data reaches 9 percent at 3 GHz.
+  Theoretically, we propose an equivalent circuit model of an SRR loaded by a
+magnetic film. This model follows from the results of our numerical simulations
+of the microwave field structure of the SRR and of the magnetization dynamics
+in the YIG film driven by the microwave currents in the SRR. The equivalent
+circuit model is in good agreement with the experiment. It provides a simple
+physical explanation of the process of mode anti-crossing.
+  Our findings are important for future applications in microwave quantum
+photonic devices as well as in magnetically tunable metamaterials exploiting
+the strong coupling of magnons to microwave photons.",1409.5499v1
+2015-03-25,Rigorous numerical study of strong microwave photon-magnon coupling in all-dielectric magnetic multilayers,"We demonstrate theoretically a strong local enhancement of the intensity of
+the in-plane microwave magnetic field in multilayered structures made from a
+magneto-insulating yttrium iron garnet (YIG) layer sandwiched between two
+non-magnetic layers with a high dielectric constant matching that of YIG. The
+enhancement is predicted for the excitation regime when the microwave magnetic
+field is induced inside the multilayer by the transducer of a stripline
+Broadband Ferromagnetic Resonance (BFMR) setup. By means of a rigorous
+numerical solution of the Landau-Lifshitz-Gilbert equation consistently with
+the Maxwell's equations, we investigate the magnetisation dynamics in the
+multilayer. We reveal a strong photon-magnon coupling, which manifests itself
+as anti-crossing of the ferromagnetic resonance (FMR) magnon mode supported by
+the YIG layer and the electromagnetic resonance mode supported by the whole
+multilayered structure. The frequency of the magnon mode depends on the
+external static magnetic field, which in our case is applied tangentially to
+the multilayer in the direction perpendicular to the microwave magnetic field
+induced by the stripline of the BFMR setup. The frequency of the
+electromagnetic mode is independent of the static magnetic field. Consequently,
+the predicted photon-magnon coupling is sensitive to the applied magnetic field
+and thus can be used in magnetically tuneable metamaterials based on
+simultaneously negative permittivity and permeability achievable thanks to the
+YIG layer. We also suggest that the predicted photon-magnon coupling may find
+applications in microwave quantum information systems.",1503.07282v1
+2015-12-24,Ultra-High Cooperativity Interactions between Magnons and Resonant Photons in a YIG sphere,"Resonant photon modes of a 5mm diameter YIG sphere loaded in a cylindrical
+cavity in the 10-30GHz frequency range are characterised as a function of
+applied DC magnetic field at millikelvin temperatures. The photon modes are
+confined mainly to the sphere, and exhibited large mode filling factors in
+comparison to previous experiments, allowing ultrastrong coupling with the
+magnon spin wave resonances. The largest observed coupling between photons and
+magnons is $2g/2\pi=7.11$ GHz for a 15.5 GHz mode, corresponding to a
+cooperativity of $C=1.51\pm0.47\times10^7$. Complex modifications beyond a
+simple multi-oscillator model, of the photon mode frequencies were observed
+between 0 and 0.1 Tesla. Between 0.4 to 1 Tesla, degenerate resonant photon
+modes were observed to interact with magnon spin wave resonances with different
+couplings strengths, indicating time reversal symmetry breaking due to the
+gyrotropic permeability of YIG. Bare dielectric resonator mode frequencies were
+determined by detuning magnon modes to significantly higher frequencies with
+strong magnetic fields. By comparing measured mode frequencies at 7 Tesla with
+Finite Element modelling, a bare dielectric permittivity of $15.96\pm0.02$ of
+the YIG crystal has been determined at about $20$ mK.",1512.07773v5
+2016-01-21,Detection of spin pumping from YIG by spin-charge conversion in a Au/Ni$_{80}$Fe$_{20}$ spin-valve structure,"Many experiments have shown the detection of spin-currents driven by
+radio-frequency spin pumping from yttrium iron garnet (YIG), by making use of
+the inverse spin-Hall effect, which is present in materials with strong
+spin-orbit coupling, such as Pt. Here we show that it is also possible to
+directly detect the resonance-driven spin-current using Au/permalloy (Py,
+Ni$_{80}$Fe$_{20}$) devices, where Py is used as a detector for the spins
+pumped across the YIG/Au interface. This detection mechanism is equivalent to
+the spin-current detection in metallic non-local spin-valve devices. By finite
+element modeling we compare the pumped spin-current from a reference Pt strip
+with the detected signals from the Au/Py devices. We find that for one series
+of Au/Py devices the calculated spin pumping signals mostly match the
+measurements, within 20%, whereas for a second series of devices additional
+signals are present which are up to a factor 10 higher than the calculated
+signals from spin pumping. We also identify contributions from thermoelectric
+effects caused by the resonant (spin-related) and non-resonant heating of the
+YIG. Thermocouples are used to investigate the presence of these thermal
+effects and to quantify the magnitude of the Spin-(dependent-)Seebeck effect.
+Several additional features are observed, which are also discussed.",1601.05605v1
+2016-04-12,The effect of inserted NiO layer on spin-Hall magnetoresistance in Pt/NiO/YIG heterostructures,"We investigate the spin-current transport through antiferromagnetic insulator
+(AFMI) by means of the spin-Hall magnetoressitance (SMR) over a wide
+temperature range in Pt/NiO/Y$_3$Fe$_5$O$_{12}$ (Pt/NiO/YIG) heterostructures.
+By inserting the AFMI NiO layer, the SMR dramatically decreases by decreasing
+the temperature down to the antiferromagnetically ordered state of NiO, which
+implies that the AFM order prevents rather than promotes the spin-current
+transport. On the other hand, the magnetic proximity effect (MPE) on induced Pt
+moments by YIG, which entangles with the spin-Hall effect (SHE) in Pt, can be
+efficiently screened, and pure SMR can be derived by insertion of NiO. The dual
+roles of the NiO insertion including efficiently blocking the MPE and
+transporting the spin current from Pt to YIG are outstanding compared with
+other antiferromagnetic (AFM) metal or nonmagnetic metal (NM).",1604.03272v2
+2017-12-12,Microwave to optical photon conversion by means of travelling-wave magnons in YIG films,"In this work we study theoretically the efficiency of a travelling magnon
+based microwave to optical photon converter for applications in Quantum
+Information (QI). The converter employs an epitaxially grown yttrium iron
+garnet (YIG) film as the medium for propagation of travelling magnons (spin
+waves). The conversion is achieved through coupling of magnons to guided
+optical modes of the film. The total microwave to optical photon conversion
+efficiency is found to be larger than in a similar process employing a YIG
+sphere by at least 4 orders of magnitude. By creating an optical resonator of a
+large length from the film (such that the traveling magnon decays before
+forming a standing wave over the resonator length) one will be able to further
+increase the efficiency by several orders of magnitude, potentially reaching a
+value similar to achieved with opto-mechanical resonators. Also, as a spin-off
+result, it is shown that isolation of more that 20 dB with direct insertion
+losses about 5 dBm can be achieved with YIG film based microwave isolators for
+applications in Quantum Information.
+  An important advantage of the suggested concept of the QI devices based on
+travelling spin waves is a perfectly planar geometry and a possibility of
+implementing a the device as a hybrid opto-microwave chip.",1712.04304v2
+2018-02-09,Monocrystalline free standing 3D yttrium iron garnet magnon nano resonators,"Nano resonators in which mechanical vibrations and spin waves can be coupled
+are an intriguing concept that can be used in quantum information processing to
+transfer information between different states of excitation. Until now, the
+fabrication of free standing magnetic nanostructures which host long lived spin
+wave excitatons and may be suitable as mechanical resonators seemed elusive. We
+demonstrate the fabrication of free standing monocrystalline yttrium iron
+garnet (YIG) 3D nanoresonators with nearly ideal magnetic properties. The
+freestanding 3D structures are obtained using a complex lithography process
+including room temperature deposition and lift-off of amorphous YIG and
+subsequent crystallization by annealing. The crystallization nucleates from the
+substrate and propagates across the structure even around bends over distances
+of several micrometers to form e.g. monocrystalline resonators as shown by
+transmission electron microscopy. Spin wave excitations in individual
+nanostructures are imaged by time resolved scanning Kerr microscopy. The narrow
+linewidth of the magnetic excitations indicates a Gilbert damping constant of
+only $\alpha = 2.6 \times 10^{-4}$ rivalling the best values obtained for
+epitaxial YIG thin film material. The new fabrication process represents a leap
+forward in magnonics and magnon mechanics as it provides 3D YIG structures of
+unprecedented quality. At the same time it demonstrates a completely new route
+towards the fabrication of free standing crystalline nano structures which may
+be applicable also to other material systems.",1802.03176v2
+2018-11-29,"Effect of YIG Nanoparticle Size and Clustering in Proximity-Induced Magnetism in Graphene/YIG Composite Probed with Magnetoimpedance Sensors: Towards Improved Functionality, Sensitivity and Proximity Detection","Proximity-induced magnetism (PIM) in graphene (Gr) adjacent to magnetic
+specimen has raised great fundamental interests. The subject is under debate
+and yet no application is proposed and granted. In this paper, toward
+accomplishment of fundamental facts, we first explore the effect of particle
+size and clustering in the PIM in Gr nanoplates (GNPs)/yttrium iron garnet
+(YIG) magnetic nanoparticle (MNP) composite. Microscopic analyzes suggest that
+fine MNPs distributed uniformly on the GNPs have higher saturation
+magnetization due to the PIM in Gr. We propose that such magnetic plates can
+thus be used to shield the stray field generated on the surface of magnetic
+sensors and play a role as a magnetic lens to prevent the field emanating
+outside the body of magnetic specimen. The GNPs/YIG composites are coated on a
+magnetic ribbon and proposed for application in magneto-impedance (MI) sensors.
+We show that such planar magnetic flakes enhance the MI response against the
+external applied magnetic field significantly. The suggested application can be
+furthermore developed toward bio-sensing and magnetic shielding in different
+magnetic sensors and devices.",1811.12317v2
+2018-12-23,Temperature dependence of the effective spin-mixing conductance probed with lateral non-local spin valves,"We report the temperature dependence of the effective spin-mixing conductance
+between a normal metal (aluminium, Al) and a magnetic insulator
+($\text{Y}_3\text{Fe}_5\text{O}_{12}$, YIG). Non-local spin valve devices,
+using Al as the spin transport channel, were fabricated on top of YIG and
+SiO$_2$ substrates. By comparing the spin relaxation lengths in the Al channel
+on the two different substrates, we calculate the effective spin-mixing
+conductance ($G_\text{s}$) to be $3.3\times10^{12}$~$\Omega^{-1}\text{m}^{-2}$
+at 293~K for the Al/YIG interface. A decrease of up to 84\% in $G_\text{s}$ is
+observed when the temperature ($T$) is decreased from 293~K to 4.2~K, with
+$G_\text{s}$ scaling with $(T/T_\text{c})^{3/2}$. The real part of the
+spin-mixing conductance ($G_\text{r}\approx 5.7\times10^{13}~
+\Omega^{-1}\text{m}^{-2}$), calculated from the experimentally obtained
+$G_\text{s}$, is found to be approximately independent of the temperature. We
+evidence a hitherto unrecognized underestimation of $G_\text{r}$ extracted from
+the modulation of the spin signal by rotating the magnetization direction of
+YIG with respect to the spin accumulation direction in the Al channel, which is
+found to be 50 times smaller than the calculated value.",1812.09766v1
+2019-05-11,Giant Spin Seebeck Effect through an Interface Organic Semiconductor,"Interfacing an organic semiconductor C60 with a non-magnetic metallic thin
+film (Cu or Pt) has created a novel heterostructure that is ferromagnetic at
+ambient temperature, while its interface with a magnetic metal (Fe or Co) can
+tune the anisotropic magnetic surface property of the material. Here, we
+demonstrate that sandwiching C60 in between a magnetic insulator (Y3Fe5O12:
+YIG) and a non-magnetic, strong spin-orbit metal (Pt) promotes highly efficient
+spin current transport via the thermally driven spin Seebeck effect (SSE).
+Experiments and first principles calculations consistently show that the
+presence of C60 reduces significantly the conductivity mismatch between YIG and
+Pt and the surface perpendicular magnetic anisotropy of YIG, giving rise to
+enhanced spin mixing conductance across YIG/C60/Pt interfaces. As a result, a
+600% increase in the SSE voltage (VLSSE) has been realized in YIG/C60/Pt
+relative to YIG/Pt. Temperature-dependent SSE voltage measurements on
+YIG/C60/Pt with varying C60 layer thicknesses also show an exponential increase
+in VLSSE at low temperatures below 200 K, resembling the temperature evolution
+of spin diffusion length of C60. Our study emphasizes the important roles of
+the magnetic anisotropy and the spin diffusion length of the intermediate layer
+in the SSE in YIG/C60/Pt structures, providing a new pathway for developing
+novel spin-caloric materials.",1905.04555v1
+2019-10-07,Chiral spin-wave velocities induced by all-garnet interfacial Dzyaloshinskii-Moriya interaction in ultrathin yttrium iron garnet films,"Spin waves can probe the Dzyaloshinskii-Moriya interaction (DMI) which gives
+rise to topological spin textures, such as skyrmions. However, the DMI has not
+yet been reported in yttrium iron garnet (YIG) with arguably the lowest damping
+for spin waves. In this work, we experimentally evidence the interfacial DMI in
+a 7~nm-thick YIG film by measuring the nonreciprocal spin wave propagation in
+terms of frequency, amplitude and most importantly group velocities using all
+electrical spin-wave spectroscopy. The velocities of propagating spin waves
+show chirality among three vectors, i.e. the film normal direction, applied
+field and spin-wave wavevector. By measuring the asymmetric group velocities,
+we extract a DMI constant of 16~$\mu$J/m$^{2}$ which we independently confirm
+by Brillouin light scattering. Thickness-dependent measurements reveal that the
+DMI originates from the oxide interface between the YIG and garnet substrate.
+The interfacial DMI discovered in the ultrathin YIG films is of key importance
+for functional chiral magnonics as ultra-low spin-wave damping can be achieved.",1910.02599v2
+2019-12-01,Differences in the magnon diffusion length for electrically and thermally driven magnon currents in Y$_3$Fe$_5$O$_{12}$,"Recent demonstration of efficient transport and manipulation of spin
+information by magnon currents have opened exciting prospects for processing
+information in devices. Magnon currents can be driven both electrically and
+thermally, even in magnetic insulators, by applying charge currents in an
+adjacent metal layer. Earlier reports in thin yttrium iron garnet (YIG) films
+suggested that the diffusion length of magnons is independent on the biasing
+method, but different values were obtained in thicker films. Here, we study the
+magnon diffusion length for electrically and thermally driven magnon currents
+in the linear regime in a 2-$\mu$m-thick YIG film as a function of temperature
+and magnetic field. Our results show a decrease of the magnon diffusion length
+with magnetic field for both biasing methods and at all temperatures from 5 to
+300 K, indicating that sub-thermal magnons dominate the long-range transport.
+Moreover, we demonstrate that the value of the magnon diffusion length depends
+on the driving mechanism, suggesting that different non-equilibrium magnon
+distributions are biased for each method. Finally, we demonstrate that the
+magnon diffusion length for thermally driven magnon currents is independent of
+the YIG thickness and material growth conditions, confirming that this quantity
+is an intrinsic parameter of YIG.",1912.00490v2
+2020-09-06,Enhancement of YIG$|$Pt spin conductance by local Joule annealing,"We report that Joule heating can be used to enhance the interfacial spin
+conductivity between a metal and an oxide. We observe that local annealing of
+the interface at about 550\,K by injecting large current densities
+($>10^{12}\text{A/m}^{2}$) into a pristine 7\,nm thick Pt nanostrip evaporated
+on top of yttrium iron garnet (YIG), can improve the spin transmission up to a
+factor 3: a result of particular interest for interfacing ultra thin garnet
+films where strong chemical etching of the surface has to be avoided. The
+effect is confirmed by different methods: spin Hall magnetoresistance, spin
+pumping and non-local spin transport. We use it to study the influence of the
+YIG$|$Pt coupling on the non-linear spin transport properties. We find that the
+cross-over current from a linear to a non-linear spin transport regime is
+independent of this coupling, suggesting that the behavior of pure spin
+currents circulating in the dielectric are mostly governed by the physical
+properties of the bare YIG film beside the Pt nanostrip.",2009.02785v1
+2021-04-19,Magnetic coupling in Y$_3$Fe$_5$O$_{12}$/Gd$_3$Fe$_5$O$_{12}$ heterostructures,"Ferrimagnetic Y$_3$Fe$_5$O$_{12}$ (YIG) is the prototypical material for
+studying magnonic properties due to its exceptionally low damping. By
+substituting the yttrium with other rare earth elements that have a net
+magnetic moment, we can introduce an additional spin degree of freedom. Here,
+we study the magnetic coupling in epitaxial
+Y$_3$Fe$_5$O$_{12}$/Gd$_3$Fe$_5$O$_{12}$ (YIG/GIG) heterostructures grown by
+pulsed laser deposition. From bulk sensitive magnetometry and surface sensitive
+spin Seebeck effect (SSE) and spin Hall magnetoresistance (SMR) measurements,
+we determine the alignment of the heterostructure magnetization through
+temperature and external magnetic field. The ferromagnetic coupling between the
+Fe sublattices of YIG and GIG dominates the overall behavior of the
+heterostructures. Due to the temperature dependent gadolinium moment, a
+magnetic compensation point of the total bilayer system can be identified. This
+compensation point shifts to lower temperatures with increasing thickness of
+YIG due the parallel alignment of the iron moments. We show that we can control
+the magnetic properties of the heterostructures by tuning the thickness of the
+individual layers, opening up a large playground for magnonic devices based on
+coupled magnetic insulators. These devices could potentially control the magnon
+transport analogously to electron transport in giant magnetoresistive devices.",2104.09592v1
+2023-09-06,Strong magnon-magnon coupling in an ultralow damping all-magnetic-insulator heterostructure,"Magnetic insulators such as yttrium iron garnets (YIGs) are of paramount
+importance for spin-wave or magnonic devices as their ultralow damping enables
+ultralow power dissipation that is free of Joule heating, exotic magnon quantum
+state, and coherent coupling to other wave excitations. Magnetic insulator
+heterostructures bestow superior structural and magnetic properties and house
+immense design space thanks to the strong and engineerable exchange interaction
+between individual layers. To fully unleash their potential, realizing low
+damping and strong exchange coupling simultaneously is critical, which often
+requires high quality interface. Here, we show that such a demand is realized
+in an all-insulator thulium iron garnet (TmIG)/YIG bilayer system. The ultralow
+dissipation rates in both YIG and TmIG, along with their significant spin-spin
+interaction at the interface, enable strong and coherent magnon-magnon coupling
+with a benchmarking cooperativity value larger than the conventional
+ferromagnetic metal-based heterostructures. The coupling strength can be tuned
+by varying the magnetic insulator layer thickness and magnon modes, which is
+consistent with analytical calculations and micromagnetic simulations. Our
+results demonstrate TmIG/YIG as a novel platform for investigating hybrid
+magnonic phenomena and open opportunities in magnon devices comprising
+all-insulator heterostructures.",2309.03116v1
+2023-09-16,Exploring orbital-charge conversion mediated by interfaces with copper through spin-orbital pumping,"We investigated how different materials affect the orbital-charge conversion
+in heterostructures with the naturally oxidized cooper capping layer. When we
+added a thin layer of $CuOx(3nm)$ onto yttrium iron garnet $(YIG)/W$ stacks, we
+observed a significant reduction in the charge current signal measured by means
+the spin pumping effect technique. This finding contrasts with the results of a
+prior study conducted on YIG/Pt/CuOx, which reported the opposite effect. On
+the other hand, when we added the same $CuOx(3nm)$ layer to $YIG/Ti(4nm)$
+structures, there was not much change in the spin pumping signal. This occurred
+because Ti does not generate much orbital current at the $Ti/CuOx$ interface,
+unlike Pt, due to its weaker spin-orbit coupling. Interestingly, when we added
+the $CuOx(3nm)$ layer to $SiO_{2}/Py(5nm)/Pt(4nm)$ structures, the spin pumping
+signal increased. However, in $SiO_{2}/CuOx(3nm)/Pt(4nm)/Py(5nm)$ structures,
+the signal decreased. Finally, we delve into a theoretical analysis of the spin
+(orbital) Hall effect in YIG/Heavy-metal systems. These findings have the
+potential to advance research in the innovative field of orbitronics and
+contribute to the development of new technologies based on spin-orbital
+conversion.",2309.08857v2
+2023-12-22,Magnon-assisted magnetization reversal of Ni81Fe19 nanostripes on Y3Fe5O12 with different interfaces,"Magnetic bit writing by short-wave magnons without conversion to the
+electrical domain is expected to be a game-changer for in-memory computing
+architectures. Recently, the reversal of nanomagnets by propagating magnons was
+demonstrated. However, experiments have not yet explored different wavelengths
+and the nonlinear excitation regime of magnons required for computational
+tasks. We report on the magnetization reversal of individual 20-nm-thick
+Ni81Fe19 (Py) nanostripes integrated onto 113-nm-thick yttrium iron garnet
+(YIG). We suppress direct interlayer exchange coupling by an intermediate layer
+such as Cu and SiO2. Exciting magnons in YIG with wavelengths {\lambda} down to
+148 nm we observe the reversal of the integrated ferromagnets in a small
+opposing field of 14 mT. Magnons with a small wavelength of {\lambda} = 195 nm,
+i.e., twice the width of the Py nanostripes, induced the reversal at an
+unprecedentedly small spin precessional power of about 1 nW after propagating
+over 15 {\mu}m in YIG. Considerations based on dynamic dipolar coupling explain
+the observed wavelength dependence of magnon-induced reversal efficiency. For
+an increased power the stripes reversed in an opposing field of only about 1
+mT. Our findings are important for the practical implementation of nonvolatile
+storage of broadband magnon signals in YIG by means of bistable nanomagnets
+without the need of an appreciable global magnetic field.",2312.15107v1
+2009-02-18,Theory of coherence in Bose-Einstein condensation phenomena in a microwave driven interacting magnon gas,"Strong experimental evidences of the formation of quasi-equilibrium
+Bose-Einstein condensation (BEC) of magnons at room temperature in a film of
+yttrium iron garnet (YIG) excited by microwave radiation have been recently
+reported. Here we present a theory for the magnon gas driven by a microwave
+field far out of equilibrium showing that the nonlinear magnetic interactions
+create cooperative mechanisms for the onset of a phase transition leading to
+the spontaneous generation of quantum coherence and magnetic dynamic order in a
+macroscopic scale. The theory provides rigorous support for the formation of a
+BEC of magnons in a YIG film magnetized in the plane. We show that the system
+develops coherence only when the microwave driving power exceeds a threshold
+value and that the theoretical result for the intensity of the Brillouin light
+scattering from the BEC as a function of power agrees with the experimental
+data. The theory also explains quantitatively experimental measurements of
+microwave emission from the uniform mode generated by the confluence of BEC
+magnon pairs in a YIG film when the driving power exceeds a critical value.",0902.3138v1
+2012-06-28,Frequency and power dependence of spin-current emission by spin pumping in a thin film YIG/Pt system,"This paper presents the frequency dependence of the spin current emission in
+a hybrid ferrimagnetic insulator/normal metal system. The system is based on a
+ferrimagnetic insulating thin film of Yttrium Iron Garnet (YIG, 200 nm) grown
+by liquid-phase-epitaxy (LPE) coupled with a normal metal with a strong
+spin-orbit coupling (Pt, 15 nm). The YIG layer presents an isotropic behaviour
+of the magnetization in the plane, a small linewidth, and a roughness lower
+than 0.4 nm. Here we discuss how the voltage signal from the spin current
+detector depends on the frequency [0.6 - 7 GHz], the microwave power, Pin, [1 -
+70 mW], and the in-plane static magnetic field. A strong enhancement of the
+spin current emission is observed at low frequencies, showing the appearance of
+non-linear phenomena.",1206.6671v2
+2013-07-10,"Scaling of spin Hall angle in 3d, 4d and 5d metals from Y3Fe5O12/metal spin pumping","Pure spin currents generated by spin pumping in ferromagnet/nonmagnet (FM/NM)
+bilayers produce inverse spin Hall effect (ISHE) voltages in the NM, from which
+spin pumping and transport characteristics of the NM can be extracted. Due to
+its exceptionally low damping, Y3Fe5O12 (YIG) is an important and widely used
+FM for microwave devices and ferromagnetic resonance (FMR) spin pumping. Here
+we report systematic investigation of spin pumping from 20-nm thick YIG thin
+films to a series of 3d, 4d and 5d normal metals (Cu, Ag, Ta, W, Pt and Au)
+with various spin-orbit coupling strengths. From enhanced Gilbert damping
+obtained from the frequency dependence of FMR linewidths and ISHE signals, the
+spin Hall angles and YIG/NM interfacial spin mixing conductances are
+quantitatively determined for these metals. The spin Hall angles largely vary
+as the fourth power of the atomic number, corroborating the dominant role of
+spin-orbit coupling across a broad range in the inverse spin Hall effect.",1307.2648v2
+2013-08-01,Inverse Spin Hall Effect in nanometer-thick YIG/Pt system,"High quality nanometer-thick (20 nm, 7 nm and 4 nm) epitaxial YIG films have
+been grown on GGG substrates using pulsed laser deposition. The Gilbert damping
+coefficient for the 20 nm thick films is 2.3 x 10-4 which is the lowest value
+reported for sub-micrometric thick films. We demonstrate Inverse spin Hall
+effect (ISHE) detection of propagating spin waves using Pt. The amplitude and
+the lineshape of the ISHE voltage correlate well to the increase of the Gilbert
+damping when decreasing thickness of YIG. Spin Hall effect based
+loss-compensation experiments have been conducted but no change in the
+magnetization dynamics could be detected.",1308.0192v1
+2013-09-09,Sub-microsecond fast temporal evolution of the spin Seebeck effect,"We present temporal evolution of the spin Seebeck effect in a YIG|Pt bilayer
+system. Our findings reveal that this effect is a sub-microseconds fast
+phenomenon governed by the temperature gradient and the thermal magnons
+diffusion in the magnetic materials. A comparison of experimental results with
+the thermal-driven magnon-diffusion model shows that the temporal behavior of
+this effect depends on the time development of the temperature gradient in the
+vicinity of the YIG|Pt interface. The effective thermal-magnon diffusion length
+for YIG|Pt systems is estimated to be around 700nm.",1309.2164v1
+2014-10-07,Y3Fe5O12 Spin Pumping for Quantitative Understanding of Pure Spin Transport and Spin Hall Effect in a Broad Range of Materials,"Using Y3Fe5O12 (YIG) thin films grown by our sputtering technique, we study
+dynamic spin transport in nonmagnetic (NM), ferromagnetic (FM) and
+antiferromagnetic (AF) materials by ferromagnetic resonance (FMR) spin pumping.
+From both inverse spin Hall effect (ISHE) and damping enhancement, we determine
+the spin mixing conductance and spin Hall angle in many metals. Surprisingly,
+we observe robust spin conduction in AF insulators excited by an adjacent YIG
+at resonance. This demonstrates that YIG spin pumping is a powerful and
+versatile tool for understanding spin Hall physics, spin-orbit coupling (SOC),
+and magnetization dynamics in a broad range of materials.",1410.1597v1
+2014-10-22,Spin current generation from sputtered Y3Fe5O12 films,"Spin current injection from sputtered yttrium iron garnet (YIG) films into an
+adjacent platinum layer has been investigated by means of the spin pumping and
+the spin Seebeck effects. Films with a thickness of 83 and 96 nanometers were
+fabricated by on-axis magnetron rf sputtering at room temperature and
+subsequent post-annealing. From the frequency dependence of the ferromagnetic
+resonance linewidth, the damping constant has been estimated to be
+$(7.0\pm1.0)\times 10^{-4}$. Magnitudes of the spin current generated by the
+spin pumping and the spin Seebeck effect are of the same order as values for
+YIG films prepared by liquid phase epitaxy. The efficient spin current
+injection can be ascribed to a good YIG|Pt interface, which is confirmed by the
+large spin-mixing conductance $(2.0\pm0.2)\times 10^{18}$ m$^{-2}$.",1410.5987v1
+2014-12-07,Magnonic band gaps in YIG based magnonic crystals: array of grooves versus array of metallic stripes,"The magnonic band gaps of the two types of planar one-dimensional magnonic
+crystals comprised of the periodic array of the metallic stripes on yttrium
+iron garnet (YIG) film and YIG film with an array of grooves was analyzed
+experimentally and theoretically. In such periodic magnetic structures the
+propagating magnetostatic surface spin waves were excited and detected by
+microstripe transducers with vector network analyzer and by Brillouin light
+scattering spectroscopy. Properties of the magnonic band gaps were explained
+with the help of the finite element calculations. The important influence of
+the nonreciprocal properties of the spin wave dispersion induced by metallic
+stripes on the magnonic band gap width and its dependence on the external
+magnetic field has been shown. The usefulness of both types of the magnonic
+crystals for potential applications and possibility for miniaturization are
+discussed.",1412.2367v2
+2014-12-22,Surface sensitivity of the spin Seebeck effect,"We have investigated the influence of the interface quality on the spin
+Seebeck effect (SSE) of the bilayer system yttrium iron garnet (YIG) - platinum
+(Pt). The magnitude and shape of the SSE is strongly influenced by mechanical
+treatment of the YIG single crystal surface. We observe that the saturation
+magnetic field H_{sat} for the SSE signal increases from 55.3 mT to 72.8 mT
+with mechanical treatment. The change in the magnitude of H_{sat} can be
+attributed to the presence of a perpendicular magnetic anisotropy due to the
+treatment induced surface strain or shape anisotropy in the Pt/YIG system. Our
+results show that the SSE is a powerful tool to investigate magnetic anisotropy
+at the interface.",1412.7712v1
+2015-02-18,Spectral shape deformation in inverse spin Hall voltage in Y3Fe5O12|Pt bilayers at high microwave power levels,"We report on the deformation of microwave absorption spectra and of the
+inverse spin Hall voltage signals in thin film bilayers of yttrium iron garnet
+(YIG) and platinum at high microwave power levels in a 9.45-GHz TE011 cavity.
+As the microwave power increases from 0.15 to 200 mW, the resonance field
+shifts to higher values, and the initially Lorentzian spectra of the microwave
+absorption intensity as well as the inverse spin Hall voltage signals become
+asymmetric. The contributions from opening of the magnetization precession cone
+and heating of YIG cannot well reproduce the data. Control measurements of
+inverse spin Hall voltages on thin-film YIG|Pt systems with a range of line
+widths underscore the role of spin-wave excitations in spectral deformation.",1502.05198v1
+2015-02-13,Spin-current injection and detection in strongly correlated organic conductor,"Spin-current injection into an organic semiconductor
+$\rm{\kappa\text{-}(BEDT\text{-}TTF)_2Cu[N(CN)_2]Br}$ film induced by the spin
+pumping from an yttrium iron garnet (YIG) film. When magnetization dynamics in
+the YIG film is excited by ferromagnetic or spin-wave resonance, a voltage
+signal was found to appear in the
+$\rm{\kappa\text{-}(BEDT\text{-}TTF)_2Cu[N(CN)_2]Br}$ film.
+Magnetic-field-angle dependence measurements indicate that the voltage signal
+is governed by the inverse spin Hall effect in
+$\rm{\kappa\text{-}(BEDT\text{-}TTF)_2Cu[N(CN)_2]Br}$. We found that the
+voltage signal in the $\rm{\kappa\text{-}(BEDT\text{-}TTF)_2Cu[N(CN)_2]Br}$/YIG
+system is critically suppressed around 80 K, around which magnetic and/or glass
+transitions occur, implying that the efficiency of the spin-current injection
+is suppressed by fluctuations which critically enhanced near the transitions.",1502.05244v1
+2015-04-03,The effect of the magnon dispersion on the longitudinal spin Seebeck effect in yttrium iron garnets (YIG),"We study the temperature dependence of the longitudinal spin-Seebeck effect
+(LSSE) in a yttrium iron garnet Y3Fe5O12 (YIG) / Pt system for samples of
+different thicknesses. In this system, the thermal spin torque is
+magnon-driven. The LSSE signal peaks at a specific temperature that depends on
+the YIG sample thickness. We also observe freeze-out of the LSSE signal at high
+magnetic fields, which we attribute to the opening of an energy gap in the
+magnon dispersion. We observe partial freeze-out of the LSSE signal even at
+room temperature, where kBT is much larger than the gap. This suggests that a
+subset of the magnon population with an energy below kB x TC (TC about 40 K)
+contribute disproportionately to the LSSE; at temperatures below TC, we label
+these magnons subthermal magnons. The T-dependence of the LSSE at temperatures
+below the maximum is interpreted in terms of a new empirical model that
+ascribes most of the temperature dependence to that of the thermally driven
+magnon flux.",1504.00895v1
+2015-09-14,Antiferromagnonic Spin Transport from Y$_3$Fe$_5$O$_{12}$ into NiO,"We observe highly efficient dynamic spin injection from Y$_3$Fe$_5$O$_{12}$
+(YIG) into NiO, an antiferromagnetic (AF) insulator, via strong coupling, and
+robust spin propagation in NiO up to 100-nm thickness mediated by its AF spin
+correlations. Strikingly, the insertion of a thin NiO layer between YIG and Pt
+significantly enhances the spin currents driven into Pt, suggesting
+exceptionally high spin transfer efficiency at both YIG/NiO and NiO/Pt
+interfaces. This offers a powerful platform for studying AF spin pumping and AF
+dynamics as well as for exploration of spin manipulation in tailored structures
+comprising metallic and insulating ferromagnets, antiferromagnets and
+nonmagnetic materials.",1509.04337v1
+2016-04-13,Magnon spin transport driven by the magnon chemical potential in a magnetic insulator,"We develop a linear-response transport theory of diffusive spin and heat
+transport by magnons in magnetic insulators with metallic contacts. The magnons
+are described by a position dependent temperature and chemical potential that
+are governed by diffusion equations with characteristic relaxation lengths.
+Proceeding from a linearized Boltzmann equation, we derive expressions for
+length scales and transport coefficients. For yttrium iron garnet (YIG) at room
+temperature we find that long-range transport is dominated by the magnon
+chemical potential. We compare the model's results with recent experiments on
+YIG with Pt contacts [L.J. Cornelissen, et al., Nat. Phys. 11, 1022 (2015)] and
+extract a magnon spin conductivity of $\sigma_{m}=5\times10^{5}$ S/m. Our
+results for the spin Seebeck coefficient in YIG agree with published
+experiments. We conclude that the magnon chemical potential is an essential
+ingredient for energy and spin transport in magnetic insulators.",1604.03706v1
+2016-04-17,Interface electronic structure at the topological insulator - ferrimagnetic insulator junction,"An interface electron state at the junction between a three-dimensional
+topological insulator (TI) film of Bi2Se3 and a ferrimagnetic insulator film of
+Y3Fe5O12 (YIG) was investigated by measurements of angle-resolved photoelectron
+spectroscopy and X-ray absorption magnetic circular dichroism (XMCD). The
+surface state of the Bi2Se3 film was directly observed and localized 3d spin
+states of the Fe3+ state in the YIG film were confirmed. The proximity effect
+is likely described in terms of the exchange interaction between the localized
+Fe 3d electrons in the YIG film and delocalized electrons of the surface and
+bulk states in the Bi2Se3 film. The Curie temperature (TC) may be increased by
+reducing the amount of the interface Fe2+ ions with opposite spin direction
+observable as a pre-edge in the XMCD spectra.",1604.04869v1
+2016-05-27,Combined Brillouin light scattering and microwave absorption study of magnon-photon coupling in a split-ring resonator/YIG film system,"Microfocused Brillouin light scattering (BLS) and microwave absorption (MA)
+are used to study magnon-photon coupling in a system consisting of a split-ring
+microwave resonator and a yttrium iron garnet (YIG) film. The split-ring
+resonantor is defined by optical lithography and loaded with a 1 $\mu$m-thick
+YIG film grown by liquid phase epitaxy. BLS and MA spectra of the hybrid system
+are simultaneously recorded as a function of the applied magnetic field
+magnitude and microwave excitation frequency. Strong coupling of the magnon and
+photon modes is found with a coupling strength of $g_\text{eff}/2 \pi = 63$
+MHz. The combined BLS and MA data allows to study the continuous transition of
+the hybridized modes from a purely magnonic to a purely photonic mode by
+varying the applied magnetic field and microwave frequency. Furthermore, the
+BLS data represent an up-conversion of the microwave frequency coupling to
+optical frequencies.",1605.08531v1
+2016-07-08,Control of magnon-photon coupling strength in a planar resonator/YIG thin film configuration,"A systematic study of the coupling at room temperature between ferromagnetic
+resonance (FMR) and a planar resonator is presented. The chosen magnetic
+material is a ferrimagnetic insulator (Yttrium Iron Garnet: YIG) which is
+positioned on top of a stop band (notch) filter based on a stub line
+capacitively coupled to a 50 $\Omega$ microstrip line resonating at 4.731 GHz.
+Control of the magnon-photon coupling strength is discussed in terms of the
+microwave excitation configuration and the YIG thickness from 0.2 to 41 $\mu$m.
+From the latter dependence, we extract a single spin-photon coupling of
+g$_{0}$/2$\pi$=162$\pm$6 mHz and a maximum of an effective coupling of 290 MHz.",1607.02358v3
+2016-07-25,Damping of parametrically excited magnons in the presence of the longitudinal spin Seebeck effect,"The impact of the longitudinal spin Seebeck effect (LSSE) on the magnon
+damping in magnetic-insulator/nonmagnetic-metal bilayers was recently discussed
+in several reports. However, results of those experiments can be blurred by
+multimode excitation within the measured linewidth. In order to avoid possible
+intermodal interference, we investigated the damping of a single magnon group
+in a platinum covered Yttrium Iron Garnet (YIG) film by measurement of the
+threshold of its parametric excitation. Both dipolar and exchange spin-wave
+branches were probed. It turned out that the LSSE-related modification of
+spin-wave damping in a micrometer-thick YIG film is too weak to be observed in
+the entire range of experimentally accessible wavevectors. At the same time,
+the change in the mean temperature of the YIG layer, which can appear by
+applying a temperature gradient, strongly modifies the damping value.",1607.07274v1
+2016-09-26,Magnon Kerr effect in a strongly coupled cavity-magnon system,"We experimentally demonstrate magnon Kerr effect in a cavity-magnon system,
+where magnons in a small yttrium iron garnet (YIG) sphere are strongly but
+dispersively coupled to the photons in a three-dimensional cavity. When the YIG
+sphere is pumped to generate considerable magnons, the Kerr effect yields a
+perceptible shift of the cavity's central frequency and more appreciable shifts
+of the magnon modes. We derive an analytical relation between the magnon
+frequency shift and the drive power for the uniformly magnetized YIG sphere and
+find that it agrees very well with the experimental results of the Kittel mode.
+Our study paves the way to explore nonlinear effects in the cavity-magnon
+system.",1609.07891v2
+2016-09-24,Optical manipulation of a magnon-photon hybrid system,"We demonstrate an all-optical method for manipulating the magnetization in a
+1-mm YIG (yttrium-iron-garnet) sphere placed in a $\sim0.17\,$T uniform
+magnetic field. An harmonic of the frequency comb delivered by a multi-GHz
+infrared laser source is tuned to the Larmor frequency of the YIG sphere to
+drive magnetization oscillations, which in turn give rise to a radiation field
+used to thoroughly investigate the phenomenon. The radiation damping issue that
+occurs at high frequency and in the presence of highly magnetizated materials,
+has been overcome by exploiting magnon-photon strong coupling regime in
+microwave cavities. Our findings demonstrate an effective technique for
+ultrafast control of the magnetization vector in optomagnetic materials via
+polarization rotation and intensity modulation of an incident laser beam. We
+eventually get a second-order susceptibility value of $\sim10^{-7}$ cm$^2$/MW
+for single crystal YIG.",1609.08147v1
+2016-10-27,Spin-wave propagation in ultra-thin YIG based waveguides,"Spin-wave propagation in an assembly of microfabricated 20 nm thick, 2.5
+{\mu}m wide Yttrium Iron Garnet (YIG) waveguides is studied using propagating
+spin-wave spectroscopy (PSWS) and phase resolved micro-focused Brillouin Light
+Scattering ({\mu}-BLS) spectroscopy. We show that spin-wave propagation in 50
+parallel waveguides is robust against microfabrication induced imperfections.
+Spin-wave propagation parameters are studied in a wide range of excitation
+frequencies for the Damon-Eshbach (DE) configuration. As expected from its low
+damping, YIG allows the propagation of spin waves over long distances (the
+attenuation lengths is 25 {\mu}m at \mu$_{0}$H = 45 mT). Direct mapping of spin
+waves by {\mu}-BLS allows us to reconstruct the spin-wave dispersion relation
+and to confirm the multi-mode propagation in the waveguides, glimpsed by
+propagating spin-wave spectroscopy.",1610.08756v1
+2016-12-06,Increased low-temperature damping in yttrium iron garnet thin films,"We report measurements of the frequency and temperature dependence of
+ferromagnetic resonance (FMR) for a 15-nm-thick yttrium iron garnet (YIG) film
+grown by off-axis sputtering. Although the FMR linewidth is narrow at room
+temperature (corresponding to a damping coefficient $\alpha$ = (9.0 $\pm$ 0.2)
+$\times 10^{-4}$), comparable to previous results for high-quality YIG films of
+similar thickness, the linewidth increases strongly at low temperatures, by a
+factor of almost 30. This increase cannot be explained as due to two-magnon
+scattering from defects at the sample interfaces. We argue that the increased
+low-temperature linewidth is due to impurity relaxation mechanisms that have
+been investigated previously in bulk YIG samples. We suggest that the
+low-temperature linewidth is a useful figure of merit to guide the optimization
+of thin-film growth protocols because it is a particularly sensitive indicator
+of impurities.",1612.01954v1
+2016-12-24,Concomitant enhancement of longitudinal spin Seebeck effect with thermal conductivity,"We report a simultaneous measurement of a longitudinal spin Seebeck effect
+(LSSE) and thermal conductivity in a Pt/${\rm Y_{3}Fe_{5}O_{12}}$ (YIG)/Pt
+system in a temperature range from 10 to 300 K. By directly monitoring the
+temperature difference in the system, we excluded thermal artifacts in the LSSE
+measurements. It is found that both the LSSE signal and the thermal
+conductivity of YIG exhibit sharp peaks at the same temperature, differently
+from previous reports. The maximum LSSE coefficient is found to be
+$S{\rm_{LSSE}}>10\ \mu{\rm V/K}$, one-order-of magnitude greater than the
+previously reported values. The concomitant enhancement of the LSSE and thermal
+conductivity of YIG suggests the strong correlation between magnon and phonon
+transport in the LSSE.",1612.08142v1
+2017-01-19,Separation of inverse spin Hall effect and anomalous Nernst effect in ferromagnetic metals,"Inverse spin Hall effect (ISHE) in ferromagnetic metals (FM) can also be used
+to detect the spin current generated by longitudinal spin Seebeck effect in a
+ferromagnetic insulator YIG. However, anomalous Nernst effect(ANE) in FM itself
+always mixes in the thermal voltage. In this work, the exchange bias structure
+(NiFe/IrMn)is employed to separate these two effects. The exchange bias
+structure provides a shift field to NiFe, which can separate the magnetization
+of NiFe from that of YIG in M-H loops. As a result, the ISHE related to
+magnetization of YIG and the ANE related to the magnetization of NiFe can be
+separated as well. By comparison with Pt, a relative spin Hall angle of NiFe
+(0.87) is obtained, which results from the partially filled 3d orbits and the
+ferromagnetic order. This work puts forward a practical method to use the ISHE
+in ferromagnetic metals towards future spintronic applications.",1701.05320v1
+2017-03-16,All-Angle Collimation for Spin Waves,"We studied the effect of collimation for monochromatic beams of spin waves,
+resulting from the refraction at the interface separating two magnetic
+half-planes. The collimation was observed in broad range of the angles of
+ncidence for homogenous Co and Py half-planes, due to significant intrinsic
+anisotropy of spin wave propagation in these materials. The effect exists for
+the sample saturated by in plane magnetic field tangential to the interface.
+The collimation for all possible angles of incidence was found in the system
+where the incident spin wave is refracted on the interface between homogeneous
+and periodically patterned layers of YIG. The refraction was investigated by
+the analysis of isofrequency dispersion contours of both pairs materials, i.e.,
+uniform YIG/patterned YIG and Co/Py, which are calculated with the aid of the
+plane wave method. Besides, the refraction in Co/Py system was studied using
+micromagnetic simulations.",1703.05548v1
+2017-04-10,Patterned growth of crystalline Y$_{3}$Fe$_{5}$O$_{12}$ nanostructures with engineered magnetic shape anisotropy,"We demonstrate patterned growth of epitaxial yttrium iron garnet (YIG) thin
+films using lithographically defined templates on gadolinium gallium garnet
+(GGG) substrates. The fabricated YIG nanostructures yield the desired
+crystallographic orientation, excellent surface morphology, and narrow
+ferromagnetic resonance (FMR) linewidth (~ 4 Oe). Shape-induced magnetic
+anisotropy is clearly observed in a patterned array of nanobars engineered to
+exhibit the larger coercivity (40 Oe) compared with that of continuous films.
+Both hysteresis loop and angle-dependent FMR spectra measurements indicate that
+the easy axis aligns along the longitudinal direction of the nanobars, with an
+effective anisotropy field of 195 Oe. Our work overcomes difficulties in
+patterning YIG thin films and provides an effective means to control their
+magnetic properties and magnetic bias conditions.",1704.03056v2
+2017-06-06,Observation of spin superfluidity: YIG magnetic films and beyond,"From topology of the order parameter of the magnon condensate observed in
+yttrium-iron-garnet (YIG) magnetic films one must not expect energetic barriers
+making spin supercurrents metastable. But we show that some barriers of
+dynamical origin are possible nevertheless until the gradient of the phase
+(angle of spin precession) does not exceed the critical value (analog of the
+Landau critical velocity in superfluids). On the other hand, recently published
+claims of experimental detection of spin superfluidity in YIG films and
+antiferromagnets are not justified, and spin superfluidity in magnetically
+ordered solids has not yet been experimentally confirmed.",1706.01932v2
+2017-06-27,Evidence for the role of the magnon energy relaxation length in the Spin Seebeck Effect,"Temperature-dependent spin-Seebeck effect data on Pt|YIG
+(Y$_3$Fe$_5$O$_{12}$)|GGG (Gd$_3$Ga$_5$O$_{12}$) are reported for YIG films of
+various thicknesses. The effect is reported as a spin-Seebeck resistivity
+(SSR), the inverse spin-Hall field divided by the heat flux, to circumvent
+uncertainties about temperature gradients inside the films. The SSR is a
+non-monotonic function of YIG thickness. A diffusive model for magnon transport
+demonstrates how these data give evidence for the existence of two distinct
+length scales in thermal spin transport, a spin diffusion length and a magnon
+energy relaxation length.",1706.09021v2
+2017-08-02,Strongly exchange-coupled and surface-state-modulated magnetization dynamics in Bi2Se3/YIG heterostructures,"We report strong interfacial exchange coupling in Bi2Se3/yttrium iron garnet
+(YIG) bilayers manifested as large in-plane interfacial magnetic anisotropy
+(IMA) and enhancement of damping probed by ferromagnetic resonance (FMR). The
+IMA and spin mixing conductance reached a maximum when Bi2Se3 was around 6
+quintuple-layer (QL) thick. The unconventional Bi2Se3 thickness dependence of
+the IMA and spin mixing conductance are correlated with the evolution of
+surface band structure of Bi2Se3, indicating that topological surface states
+play an important role in the magnetization dynamics of YIG.
+Temperature-dependent FMR of Bi2Se3/YIG revealed signatures of magnetic
+proximity effect of $T_c$ as high as 180 K, and an effective field parallel to
+the YIG magnetization direction at low temperature. Our study sheds light on
+the effects of topological insulators on magnetization dynamics, essential for
+development of TI-based spintronic devices.",1708.00593v1
+2017-09-26,Magnetic-field-induced suppression of spin Peltier effect in Pt/${\rm Y_{3}Fe_{5}O_{12}}$ system at room temperature,"We report the observation of magnetic-field-induced suppression of the spin
+Peltier effect (SPE) in a junction of a paramagnetic metal Pt and a
+ferrimagnetic insulator ${\rm Y_{3}Fe_{5}O_{12}}$ (YIG) at room temperature.
+For driving the SPE, spin currents are generated via the spin Hall effect from
+applied charge currents in the Pt layer, and injected into the adjacent thick
+YIG film. The resultant temperature modulation is detected by a commonly-used
+thermocouple attached to the Pt/YIG junction. The output of the thermocouple
+shows sign reversal when the magnetization is reversed and linearly increases
+with the applied current, demonstrating the detection of the SPE signal. We
+found that the SPE signal decreases with the magnetic field. The observed
+suppression rate was found to be comparable to that of the spin Seebeck effect
+(SSE), suggesting the dominant and similar contribution of the low-energy
+magnons in the SPE as in the SSE.",1709.08997v1
+2017-10-07,Magnon-phonon relaxation in yttrium iron garnet from first principles,"We combine the theoretical method of calculating spin wave excitation with
+the finite-temperature modeling and calculate the magnon-phonon relaxation time
+in the technologically important material Yttrium iron garnet (YIG) from first
+principles. The finite lifetime of magnon excitation is found to arise from the
+fluctuation of the exchange interaction of magnetic atoms in YIG. At room
+temperature, the magnon spectra have significant broadening that is used to
+extract the magnon-phonon relaxation time quantitatively. The latter is a
+phenomenological parameter of great importance in YIG-based spintronics
+research. We find that the magnon-phonon relaxation time for the optical magnon
+is a constant while that for the acoustic magnon is proportional to $1/k^2$ in
+the long-wavelength regime.",1710.02647v1
+2017-10-11,Approaching quantum anomalous Hall effect in proximity-coupled YIG/graphene/h-BN sandwich structure,"Quantum anomalous Hall state is expected to emerge in Dirac electron systems
+such as graphene under both sufficiently strong exchange and spin-orbit
+interactions. In pristine graphene, neither interaction exists; however, both
+interactions can be acquired by coupling graphene to a magnetic insulator (MI)
+as revealed by the anomalous Hall effect. Here, we show enhanced magnetic
+proximity coupling by sandwiching graphene between a ferrimagnetic insulator
+yttrium iron garnet (YIG) and hexagonal-boron nitride (h-BN) which also serves
+as a top gate dielectric. By sweeping the top-gate voltage, we observe Fermi
+level-dependent anomalous Hall conductance. As the Dirac point is approached
+from both electron and hole sides, the anomalous Hall conductance reaches 1/4
+of the quantum anomalous Hall conductance 2e2/h. The exchange coupling strength
+is determined to be as high as 27 meV from the transition temperature of the
+induced magnetic phase. YIG/graphene/h-BN is an excellent heterostructure for
+demonstrating proximity-induced interactions in two-dimensional electron
+systems.",1710.04179v1
+2018-02-12,Spin-orbit torque and spin pumping in YIG/Pt with interfacial insertion layers,"We experimentally investigate spin-orbit torque and spin pumping in
+Y$_3$Fe$_5$O$_{12}$(YIG)/Pt bilayers with ultrathin insertion layers at the
+interface. An insertion layer of Cu suppresses both spin-orbit torque and spin
+pumping, whereas an insertion layer of Ni$_{80}$Fe$_{20}$ (permalloy, Py)
+enhances them, in a quantitatively consistent manner with the reciprocity of
+the two spin transmission processes. However, we observe a large enhancement of
+Gilbert damping with the insertion of Py that cannot be accounted for solely by
+spin pumping, suggesting significant spin-memory loss due to the interfacial
+magnetic layer. Our findings indicate that the magnetization at the YIG-metal
+interface strongly influences the transmission and depolarization of pure spin
+current.",1802.03865v3
+2018-07-23,Bias dependent spin injection into graphene on YIG through bilayer hBN tunnel barriers,"We study the spin injection efficiency into single and bilayer graphene on
+the ferrimagnetic insulator Yttrium-Iron-Garnet (YIG) through an exfoliated
+tunnel barrier of bilayer hexagonal boron nitride (hBN). The contacts of two
+samples yield a resistance-area product between 5 and 30 k$\Omega\mu$m$^2$.
+Depending on an applied DC bias current, the magnitude of the non-local spin
+signal can be increased or suppressed below the noise level. The spin injection
+efficiency reaches values from -60% to +25%. The results are confirmed with
+both spin valve and spin precession measurements. The proximity induced
+exchange field is found in sample A to be (85 $\pm$ 30) mT and in sample B
+close to the detection limit. Our results show that the exceptional spin
+injection properties of bilayer hBN tunnel barriers reported by Gurram et al.
+are not limited to fully encapsulated graphene systems but are also valid in
+graphene/YIG devices. This further emphasizes the versatility of bilayer hBN as
+an efficient and reliable tunnel barrier for graphene spintronics.",1807.08481v1
+2018-10-11,"Propagating spin waves in nanometer-thick yttrium iron garnet films: Dependence on wave vector, magnetic field strength and angle","We present a comprehensive investigation of propagating spin waves in
+nanometer-thick yttrium iron garnet (YIG) films. We use broadband spin-wave
+spectroscopy with integrated coplanar waveguides (CPWs) and microstrip antennas
+on top of continuous and patterned YIG films to characterize spin waves with
+wave vectors up to 10 rad/$\mu$m. All films are grown by pulsed laser
+deposition. From spin-wave transmission spectra, parameters such as the Gilbert
+damping constant, spin-wave dispersion relation, group velocity, relaxation
+time, and decay length are derived and their dependence on magnetic bias field
+strength and angle is systematically gauged. For a 40-nm-thick YIG film, we
+obtain a damping constant of $3.5 \times 10^{-4}$ and a maximum decay length of
+1.2 mm. Our experiments reveal a strong variation of spin-wave parameters with
+magnetic bias field and wave vector. Spin-wave properties change considerably
+up to a magnetic bias field of about 30 mT and above a field angle of
+$\theta_{H} = 20^{\circ}$, where $\theta_{H} = 0^{\circ}$ corresponds to the
+Damon-Eshbach configuration.",1810.04973v1
+2018-11-14,Anomalous Hall-like transverse magnetoresistance in Au thin films on Y$_3$Fe$_5$O$_{12}$,"Anomalous Hall-like signals in platinum in contact with magnetic insulators
+are common observations that could be explained by either proximity
+magnetization or spin Hall magnetoresistance. In this work, longitudinal and
+transverse magnetoresistances are measured in a pure gold thin film on the
+ferrimagnetic insulator Y$_3$Fe$_5$O$_{12}$ (Yttrium Iron Garnet, YIG). We show
+that both the longitudinal and transverse magnetoresistances have
+quantitatively consistent scaling in YIG/Au and in a YIG/Pt reference system
+when applying the Spin Hall magnetoresistance framework. No contribution of an
+anomalous Hall effect due to the magnetic proximity effect is evident.",1811.05848v1
+2019-01-15,"SiC-YiG X band quantum sensor for sensitive surface paramagnetic resonance applied to chemistry, biology, physics","Here I present the SiC-YiG Quantum Sensor, allowing electron paramagnetic
+resonance (EPR) studies of monolayer or few nanometers thick chemical,
+biological or physical samples located on the sensor surface. It contains two
+parts, a 4H-SiC substrate with many paramagnetic silicon vacancies (V2) located
+below its surface, and YIG ferrimagnetic nanostripes. Spins sensing properties
+are based on optically detected double electron-electron spin resonance under
+the strong magnetic field gradient of nanostripes. Here I describe fabrication,
+magnetic, optical and spins sensing properties of this sensor. I show that the
+target spins sensitivity is at least five orders of magnitude larger than the
+one of standard X band EPR spectrometer, for which it constitutes, combined
+with a fiber bundle, a powerful upgrade for sensitive surface EPR. This sensor
+can determine the target spins planes EPR spectrum, their positions with a
+nanoscale precision of +/- 1 nm, and their 2D concentration down to
+1/(20nm.20nm).",1901.05073v1
+2019-01-17,Spin transport parameters of NbN thin films characterised by spin pumping experiments,"We present measurements of ferromagnetic-resonance - driven spin pumping and
+inverse spin-Hall effect in NbN/Y3Fe5O12 (YIG) bilayers. A clear enhancement of
+the (effective) Gilbert damping constant of the thin-film YIG was observed due
+to the presence of the NbN spin sink. By varying the NbN thickness and
+employing spin-diffusion theory, we have estimated the room temperature values
+of the spin diffusion length and the spin Hall angle in NbN to be 14 nm and
+-1.1 10-2, respectively. Furthermore, we have determined the spin-mixing
+conductance of the NbN/YIG interface to be 10 nm-2. The experimental
+quantification of these spin transport parameters is an important step towards
+the development of superconducting spintronic devices involving NbN thin films.",1901.05753v1
+2018-12-12,Substrate induced magnetic anisotropies and magneto-optical response in YIG nanosized epitaxial films on NdGG(111),"Nanosized Y3Fe5O12 epitaxial films have been grown on Nd3Ga5O12 substrates
+using laser molecular beam epitaxy method. Magneto-optical polar Kerr effect,
+ferromagnetic resonance and spin wave propagation measurements show that the
+stress-related anisotropy field has an opposite sign, compared to that in the
+YIG/GGG systems. This leads to a considerable decrease of the effective
+magnetization that opens a perspective to get YIG films with perpendicular
+magnetization for utilizing forward volume spin waves. Longitudinal
+magnetooptical Kerr effect magnetometry reveals a large contribution of
+quadratic in magnetization terms into dielectric permittivity tensor at optical
+frequencies. This effect strongly increases with temperature decrease and is
+explained by magnetization of the interface Nd3+ ions that are exchange coupled
+to the Fe3+ ions.",1901.10800v1
+2019-03-21,Room temperature and low-field resonant enhancement of spin Seebeck effect in partially compensated magnets,"Resonant enhancement of spin Seebeck effect (SSE) due to phonons was recently
+discovered in Y3Fe5O12 (YIG). This effect is explained by hybridization between
+the magnon and phonon dispersions. However, this effect was observed at low
+temperatures and high magnetic fields, limiting the scope for applications.
+Here we report observation of phonon-resonant enhancement of SSE at room
+temperature and low magnetic field. We observed in Lu2BiFe4GaO12 and
+enhancement 700 % greater than that in a YIG film and at very low magnetic
+fields around 10-1 T, almost one order of magnitude lower than that of YIG. The
+result can be explained by the change in the magnon dispersion induced by
+magnetic compensation due to the presence of non-magnetic ion substitutions.
+Our study provides a way to tune the magnon response in a crystal by chemical
+doping with potential applications for spintronic devices.",1903.09007v1
+2019-05-02,Anomalous spin Hall angle of a metallic ferromagnet determined by a multiterminal spin injection/detection device,"We report on the determination of the anomalous spin Hall angle in the
+ferromagnetic metal alloy cobalt-iron (Co$_{25}$Fe$_{75}$, CoFe). This is
+accomplished by measuring the spin injection/detection efficiency in a
+multiterminal device with nanowires of platinum (Pt) and CoFe deposited onto
+the magnetic insulator yttrium iron garnet (Y$_3$Fe$_5$O$_{12}$, YIG). Applying
+a spin-resistor model to our multiterminal spin transport data, we determine
+the magnon conductivity in YIG, the spin conductance at the YIG/CoFe interface
+and finally the anomalous spin Hall angle of CoFe as a function of its spin
+diffusion length in a single device. Our experiments clearly reveal a negative
+anomalous spin Hall angle of the ferromagnetic metal CoFe, but a vanishing
+ordinary spin Hall angle. This is in contrast to the results reported for the
+ferromagnetic metals Co and permalloy.",1905.00663v1
+2019-05-20,Quantum drives produce strong entanglement between YIG samples without using intrinsic nonlinearities,"We show how to generate an entangled pair of yttrium iron garnet (YIG)
+samples in a cavity-magnon system without using any nonlinearities which are
+typically very weak. This is against the conventional wisdom which necessarily
+requires strong Kerr like nonlinearity. Our key idea, which leads to
+entanglement, is to drive the cavity by a weak squeezed vacuum field generated
+by a flux-driven Josephson parametric amplifier (JPA). The two YIG samples
+interact via the cavity. For modest values of the squeezing of the pump, we
+obtain significant entanglement. This is the principal feature of our scheme.
+We discuss entanglement between macroscopic spheres using several different
+quantitative criteria. We show the optimal parameter regimes for obtaining
+entanglement which is robust against temperature. We also discuss squeezing of
+the collective magnon variables.",1905.07884v2
+2019-05-28,Broadband enhancement of the magneto-optical activity of hybrid Au loaded Bi:YIG,"We unravel the underlying near-field mechanism of the enhancement of the
+magneto-optical activity of bismuth-substituted yttrium iron garnet films
+(Bi:YIG) loaded with gold nanoparticles. The experimental results show that the
+embedded gold nanoparticles lead to a broadband enhancement of the
+magneto-optical activity with respect to the activity of the bare Bi:YIG films.
+Full vectorial near- and far-field simulations demonstrate that this broadband
+enhancement is the result of a magneto-optically enabled cross-talking of
+orthogonal localized plasmon resonances. Our results pave the way to the
+on-demand design of the magneto-optical properties of hybrid magneto-plasmonic
+circuitry.",1905.11941v1
+2019-07-15,Tuning edge localized spin waves in magnetic microstripes by proximate magnetic structures,"The propagation of edge localized spin waves (E-SWs) in yttrium iron garnet
+(YIG) microstripes with/without the proximate magnetic microstructures is
+investigated by micromagnetic simulations. A splitting of the dispersion curve
+with the presence of permalloy (Py) stripe is also observed. The E-SWs on the
+two edges of YIG stripe have different wavelengths, group velocities, and decay
+lengths at the same frequencies. The role of the Py stripe was found to be the
+source of the inhomogeneous static dipolar field without dynamic coupling with
+YIG. This work opens new perspectives for the design of innovative SW
+interference-based logic devices.",1907.06718v1
+2019-08-30,Amplitude and Phase Noise of Magnons,"The low-frequency amplitude and phase noise spectra of magnetization waves,
+i.e. magnons, was measured in the yttrium iron garnet (YIG) waveguides. This
+type of noise, which originates from the fluctuations of the physical
+properties of the YIG crystals, has to be taken into account in the design of
+YIG-based RF generators and magnonic devices for data processing, sensing and
+imaging applications. It was found that the amplitude noise level of magnons
+depends strongly on the power level, increasing sharply at the on-set of
+nonlinear dissipation. The noise spectra of both the amplitude and phase noise
+have the Lorentzian shape with the characteristic frequencies below 100 Hz.",1909.00085v1
+2019-12-25,Hybrid nanophotonic-nanomagnonic SiC-YiG quantum sensor: I/ theoretical design and properties,"Here I present the theory of a new hybrid paramagnetic-ferrimagnetic SiC-YiG
+quantum sensor. It is designed to allow sub-nanoscale single external spin
+sensitivity optically detected pulsed electron electron double resonance
+spectroscopy, using an X band pulsed EPR spectrometer and an optical fiber. The
+sensor contains one single V2 negatively charged silicon vacancy color center
+in 4H-SiC, whose photoluminescence is waveguided by a 4H-SiC nanophotonic
+structure towards an optical fiber. This V2 spin probe is created by ion
+implantation at a depth of few nanometers below the surface, determined by
+optically detected paramagnetic resonance under the strong magnetic field
+gradient of a YiG ferrimagnetic nanostripe located on the back-side of the
+nanophotonic structure. This gradient also allow the study, slice by slice at
+nanoscale, of the target paramagnetic sample. The fabrication process of this
+quantum sensor, its magnetic and optical properties, its external spins sensing
+properties in a structural biology context, and its integration to a standard
+commercially available pulsed EPR spectrometer are all presented here.",1912.11634v1
+2019-12-31,Probing magnon-magnon coupling in exchange coupled Y$_3$Fe$_5$O$_{12}$/Permalloy bilayers with magneto-optical effects,"We demonstrate the magnetically-induced transparency (MIT) effect in
+Y$_3$Fe$_5$O$_{12}$(YIG)/Permalloy(Py) coupled bilayers. The measurement is
+achieved via a heterodyne detection of the coupled magnetization dynamics using
+a single wavelength that probes the magneto-optical Kerr and Faraday effects of
+Py and YIG, respectively. Clear features of the MIT effect are evident from the
+deeply modulated ferromagnetic resonance of Py due to the
+perpendicular-standing-spin-wave of YIG. We develop a phenomenological model
+that nicely reproduces the experimental results including the induced amplitude
+and phase evolution caused by the magnon-magnon coupling. Our work offers a new
+route towards studying phase-resolved spin dynamics and hybrid magnonic
+systems.",1912.13407v2
+2020-04-20,Ultra Thin Films of Yttrium Iron Garnet with Very Low Damping: A Review,"Thin Yttrium Iron Garnet (YIG) is a promising material for integrated
+magnonics. In order to introduce YIG into nanofabrication processes it is
+necessary to fabricate very thin YIG films with a thickness well below 100 nm
+while retaining the extraordinary magnetic properties of the material,
+especially its long magnon lifetime and spin wave propagation length. Here, we
+give a brief introduction into the topic and we review and discuss the various
+results published over the last decade in this area. Especially for ultrathin
+films it turns out that pulsed layer deposition and sputtering are the most
+promising candidates. In addition, we discuss the application of room
+temperature deposition and annealing for lift-off based nanopatterning and the
+properties of nanostructures obtained by this method over the past years.",2004.09094v1
+2020-07-30,Coherent multi-mode conversion from microwave to optical wave via a magnon-cavity hybrid system,"Coherent conversion from microwave to optical wave opens new research avenues
+towards long distant quantum network covering quantum communication, computing,
+and sensing out of the laboratory. Especially multi-mode enabled system is
+essential for practical applications. Here we experimentally demonstrate
+coherent multi-mode conversion from the microwave to optical wave via
+collective spin excitation in a single crystal yttrium iron garnet (YIG,
+Y3Fe5O12) which is strongly coupled to a microwave cavity mode in a
+three-dimensional rectangular cavity. Expanding collective spin excitation mode
+of our magnon-cavity hybrid system from Kittel to multi magnetostatic modes, we
+verify that the size of YIG sphere predominantly plays a crucial role for the
+microwave-to-optical multi-mode conversion efficiency at resonant conditions.
+We also find that the coupling strength between multi magnetostatic modes and a
+cavity mode is manipulated by the position of a YIG inside the cavity. It is
+expected to be valuable for designing a magnon hybrid system that can be used
+for coherent conversion between microwave and optical photons.",2007.15299v1
+2020-08-21,Integration and characterization of micron-sized YIG structures with very low Gilbert damping on arbitrary substrates,"We present a novel process that allows the transfer of monocrystalline
+yttrium-iron-garnet microstructures onto virtually any kind of substrate. The
+process is based on a recently developed method that allows the fabrication of
+freestanding monocrystalline YIG bridges on gadolinium-gallium-garnet. Here the
+bridges' spans are detached from the substrate by a dry etching process and
+immersed in a watery solution. Using drop casting the immersed YIG platelets
+can be transferred onto the substrate of choice, where the structures finally
+can be reattached and thus be integrated into complex devices or experimental
+geometries. Using time resolved scanning Kerr microscopy and inductively
+measured ferromagnetic resonance we can demonstrate that the structures retain
+their excellent magnetic quality. At room temperature we find a ferromagnetic
+resonance linewidth of $\mu_0\Delta H_{HWHM}\approx 195\,\mu T$ and we were
+even able to inductively measure magnon spectra on a single micron-sized
+yttrium-iron-garnet platelet at a temperature of 5 K. The process is flexible
+in terms of substrate material and shape of the structure. In the future this
+approach will allow for new types of spin dynamics experiments up to now
+unthinkable.",2008.09390v1
+2020-11-12,"Experimental parameters, combined dynamics, and nonlinearity of a Magnonic-Opto-Electronic Oscillator (MOEO)","We report the construction and characterization of a comprehensive
+magnonic-opto-electronic oscillator (MOEO) system based on 1550-nm photonics
+and yttirum iron garnet (YIG) magnonics. The system exhibits a rich and
+synergistic parameter space because of the ability to control individual
+photonic, electronic, and magnonic components. Taking advantage of the spin
+wave dispersion of YIG, the frequency self-generation as well as the related
+nonlinear processes become sensitive to the external magnetic field. Besides
+being known as a narrowband filter and a delay element, the YIG delayline
+possesses spin wave modes that can be controlled to mix with the optoelectronic
+modes to generate higher-order harmonic beating modes. With the high
+sensitivity and external tunability, the MOEO system may find usefulness in
+sensing applications in magnetism and spintronics beyond optoelectronics and
+photonics.",2011.06155v1
+2021-03-16,Spin-Phonon Interaction in Yttrium Iron Garnet,"Spin-phonon interaction is an important channel for spin and energy
+relaxation in magnetic insulators. Understanding this interaction is critical
+for developing magnetic insulator-based spintronic devices. Quantifying this
+interaction in yttrium iron garnet (YIG), one of the most extensively
+investigated magnetic insulators, remains challenging because of the large
+number of atoms in a unit cell. Here, we report temperature-dependent and
+polarization-resolved Raman measurements in a YIG bulk crystal. We first
+classify the phonon modes based on their symmetry. We then develop a modified
+mean-field theory and define a symmetry-adapted parameter to quantify
+spin-phonon interaction in a phonon-mode specific way for the first time in
+YIG. Based on this improved mean-field theory, we discover a positive
+correlation between the spin-phonon interaction strength and the phonon
+frequency.",2103.09038v1
+2021-04-02,Surface plasmon-enhanced photo-magnetic excitation of spin dynamics in Au/YIG:Co magneto-plasmonic crystals,"We report strong amplification of photo-magnetic spin precession in Co-doped
+YIG employing a surface plasmon excitation in a metal-dielectric
+magneto-plasmonic crystal. Plasmonic enhancement is accompanied by the
+localization of the excitation within the 300~nm-thick layer inside the
+transparent dielectric garnet. Experimental results are nicely reproduced by
+numerical simulations of the photo-magnetic excitation. Our findings
+demonstrate the magneto-plasmonic concept of subwavelength localization and
+amplification of the photo-magnetic excitation in dielectric YIG:Co and open up
+a path to all-optical magnetization switching below diffraction limit with
+energy efficiency approaching the fundamental limit for magnetic memories.",2104.01250v1
+2021-05-24,Phase-resolved electrical detection of coherently coupled magnonic devices,"We demonstrate the electrical detection of magnon-magnon hybrid dynamics in
+yttrium iron garnet/permalloy (YIG/Py) thin film bilayer devices. Direct
+microwave current injection through the conductive Py layer excites the hybrid
+dynamics consisting of the uniform mode of Py and the first standing spin wave
+($n=1$) mode of YIG, which are coupled via interfacial exchange. Both the two
+hybrid modes, with Py or YIG dominated excitations, can be detected via the
+spin rectification signals from the conductive Py layer, providing phase
+resolution of the coupled dynamics. The phase characterization is also applied
+to a nonlocally excited Py device, revealing the additional phase shift due to
+the perpendicular Oersted field. Our results provide a device platform for
+exploring hybrid magnonic dynamics and probing their phases, which are crucial
+for implementing coherent information processing with magnon excitations",2105.11057v1
+2021-06-15,Nonreciprocal high-order sidebands induced by magnon Kerr nonlinearity,"We propose an effective approach for creating robust nonreciprocity of
+high-order sidebands, including the first-, second- and third-order sidebands,
+at microwave frequencies. This approach relies on magnon Kerr nonlinearity in a
+cavity magnonics system composed of two microwave cavities and one yttrium iron
+garnet (YIG) sphere. By manipulating the driving power applied on YIG and the
+frequency detuning between the magnon mode in YIG and the driving field, the
+effective Kerr nonlinearity can be strengthened, thereby inducing strong
+transmission non-reciprocity. More interestingly, we find the higher the
+sideband order, the stronger the transmission nonreciprocity marked by the
+higher isolation ratio in the optimal detuning regime. Such a series of
+equally-spaced high-order sidebands have potential applications in frequency
+comb-like precision measurement, besides structuring high-performance on-chip
+nonreciprocal devices.",2106.09542v1
+2021-07-12,Origin of Perpendicular Magnetic Anisotropy in Yttrium Iron Garnet Thin Films Grown on Si (100),"We report the magnetic properties of yttrium iron garnet (YIG) thin films
+grown by pulsed laser deposition technique. The films were deposited on Si
+(100) substrates in the range of 15-50 nm thickness. Magnetic characterizations
+were investigated by ferromagnetic resonance spectra. Perpendicular magnetic
+easy axis was achieved up to 50 nm thickness. We observed that the
+perpendicular anisotropy values decreased by increasing the film thickness. The
+origin of the perpendicular magnetic anisotropy (PMA) was attributed to the
+texture and the lattice distortion in the YIG thin films. We anticipate that
+perpendicularly magnetized YIG thin films on Si substrates pave the way for a
+cheaper and compatible fabrication process.",2107.05591v1
+2021-10-26,Giant quadratic magneto-optical response of thin YIG films for sensitive magnetometric experiments,"We report on observation of a magneto-optical effect quadratic in
+magnetization (Cotton-Mouton effect) in 50 nm thick layer of Yttrium-Iron
+Garnet (YIG). By a combined theoretical and experimental approach, we managed
+to quantify both linear and quadratic magneto-optical effects. We show that the
+quadratic magneto-optical signal in the thin YIG film can exceed the linear
+magneto-optical response, reaching values of 450 urad that are comparable with
+Heusler alloys or ferromagnetic semiconductors. Furthermore, we demonstrate
+that a proper choice of experimental conditions, particularly with respect to
+the wavelength, is crucial for optimization of the quadratic magneto-optical
+effect for magnetometry measurement.",2110.13679v1
+2021-10-31,Thermally induced all-optical ferromagnetic resonance in thin YIG films,"All-optical ferromagnetic resonance (AO-FMR) is a powerful tool for local
+detection of micromagnetic parameters, such as magnetic anisotropy, Gilbert
+damping or spin stiffness. In this work we demonstrate that the AO-FMR method
+can be used in thin films of Yttrium Iron Garnet (YIG) if a metallic capping
+layer (Au, Pt) is deposited on top of the film. Magnetization precession is
+triggered by heating of the metallic layer with femtosecond laser pulses. The
+heating modifies the magneto-crystalline anisotropy of the YIG film and shifts
+the quasi-equilibrium orientation of magnetization, which results in
+precessional magnetization dynamics. The laser-induced magnetization precession
+corresponds to a uniform (Kittel) magnon mode, with the precession frequency
+determined by the magnetic anisotropy of the material as well as the external
+magnetic field, and the damping time set by a Gilbert damping parameter. The
+AO-FMR method thus enables measuring local magnetic properties, with spatial
+resolution given only by the laser spot size.",2111.00586v1
+2021-11-03,Efficient geometrical control of spin waves in microscopic YIG waveguides,"We study experimentally and by micromagnetic simulations the propagation of
+spin waves in 100-nm thick YIG waveguides, where the width linearly decreases
+from 2 to 0.5 micrometers over a transition region with varying length between
+2.5 and 10 micrometers. We show that this geometry results in a down-conversion
+of the wavelength, enabling efficient generation of waves with wavelengths down
+to 350 nm. We also find that this geometry leads to a modification of the group
+velocity, allowing for almost-dispersionless propagation of spin-wave pulses.
+Moreover, we demonstrate that the influence of energy concentration outweighs
+that of damping in these YIG waveguides, resulting in an overall increase of
+the spin-wave intensity during propagation in the transition region. These
+findings can be utilized to improve the efficiency and functionality of
+magnonic devices which use spin waves as an information carrier.",2111.02236v1
+2021-12-14,Robust perpendicular magnetic anisotropy in Ce substituted yttrium iron garnet epitaxial thin films,"Cerium substituted yttrium iron garnet (Ce:YIG) epitaxial thin films are
+prepared on gadolinium gallium garnet (GGG) substrate with pulsed laser
+deposition (PLD). It is observed that the films grown on GGG(111) substrate
+exhibit perpendicular magnetic anisotropy (PMA) as compared to films grown on
+GGG(100) substrate. The developed PMA is confirmed from magneto-optical Kerr
+effect, bulk magnetization and ferromagnetic resonance measurements. Further,
+the magnetic bubble domains are observed in the films exhibiting PMA. The
+observations are explained in terms of the growth direction of Ce:YIG films and
+the interplay of various magnetic anisotropy terms. The observed PMA is found
+to be tunable with thickness of the film and a remarkable temperature stability
+of the PMA is observed in all the studied films of Ce:YIG deposited on GGG(111)
+substrate.",2112.07264v1
+2022-08-08,Effect of intense x-ray free-electron laser transient gratings on the magnetic domain structure of Tm:YIG,"Magnetic patterns can be controlled globally using fields or spin polarized
+currents. In contrast, the local control of the magnetization on the nanometer
+length scale remains challenging. Here, we demonstrate how magnetic domain
+patterns in a Tm-doped yttrium iron garnet (Tm:YIG) thin film with
+perpendicular magnetic anisotropy can be permanently and locally imprinted by
+high intensity photon pulses of a hard x-ray transient grating (XTG).
+Micromagnetic simulations provide a qualitative understanding of the observed
+changes in the orientation of magnetic domains in Tm:YIG and XTG-induced
+changes. The presented results offer a route for the local manipulation of the
+magnetic state using hard XTG.",2208.04200v2
+2022-11-01,Design of X-Band Bicontrollable Metasurface Absorber Comprising Graphene Pixels on Copper-Backed YIG Substrate,"The planewave response of a bicontrollable metasurface absorber with
+graphene-patched pixels was simulated in the X band using commercial software.
+Each square meta-atom is a 4x4 array of 16 pixels, some patched with graphene
+and the others unpatched. The pixels are arranged on a PVC skin which is placed
+on a copper-backed YIG substrate. Graphene provides electrostatic
+controllability and YIG provides magnetostatic controllability. Our design
+delivers absorptance equal to or in excess of 0.9 over a 100-MHz spectral
+regime in the X band, with 360 MHz/kA magnetostatic controllabity rate and 1 Hz
+m/V electrostatic controllability rate. Notably, electrostatic control via
+graphene in the GHz range is novel.",2211.03510v1
+2022-12-03,Strong On-Chip Microwave Photon-Magnon Coupling Using Ultra-low Damping Epitaxial Y3Fe5O12 Films at 2 Kelvin,"Y3Fe5O12 is arguably the best magnetic material for magnonic quantum
+information science (QIS) because of its extremely low damping. We report
+ultralow damping at 2 K in epitaxial Y3Fe5O12 thin films grown on a diamagnetic
+Y3Sc2Ga3O12 substrate that contains no rare-earth elements. Using these
+ultralow damping YIG films, we demonstrate for the first time strong coupling
+between magnons in patterned YIG thin films and microwave photons in a
+superconducting Nb resonator. This result paves the road towards scalable
+hybrid quantum systems that integrate superconducting microwave resonators, YIG
+film magnon conduits, and superconducting qubits into on-chip QIS devices.",2212.01708v1
+2023-08-01,Crystallization Dynamics of Amorphous Yttrium Iron Garnet Thin Films,"Yttrium iron garnet (YIG) is a prototypical material in spintronics due to
+its exceptional magnetic properties. To exploit these properties high quality
+thin films need to be manufactured. Deposition techniques like sputter
+deposition or pulsed laser deposition at ambient temperature produce amorphous
+films, which need a post annealing step to induce crystallization. However, not
+much is known about the exact dynamics of the formation of crystalline YIG out
+of the amorphous phase. Here, we conduct extensive time and temperature series
+to study the crystallization behavior of YIG on various substrates and extract
+the crystallization velocities as well as the activation energies needed to
+promote crystallization. We find that the type of crystallization as well as
+the crystallization velocity depend on the lattice mismatch to the substrate.
+We compare the crystallization parameters found in literature with our results
+and find an excellent agreement with our model. Our results allow us to
+determine the time needed for the formation of a fully crystalline film of
+arbitrary thickness for any temperature.",2308.00412v1
+2023-09-12,Anisotropy-assisted magnon condensation in ferromagnetic thin films,"We theoretically demonstrate that adding an easy-axis magnetic anisotropy
+facilitates magnon condensation in thin yttrium iron garnet (YIG) films.
+Dipolar interactions in a quasi-equilibrium state stabilize room-temperature
+magnon condensation in YIG. Even though the out-of-plane easy-axis anisotropy
+generally competes with the dipolar interactions, we show that adding such
+magnetic anisotropy may even assist the generation of the magnon condensate
+electrically via the spin transfer torque mechanism. We use analytical
+calculations and micromagnetic simulations to illustrate this effect. Our
+results may explain the recent experiment on Bi-doped YIG and open a pathway
+toward applying current-driven magnon condensation in quantum spintronics.",2309.05982v3
+2023-11-03,Cryogenic spin Peltier effect detected by a RuO$_2$-AlO$_x$ on-chip microthermometer,"We report electric detection of the spin Peltier effect (SPE) in a bilayer
+consisting of a Pt film and a Y$_{3}$Fe$_5$O$_{12}$ (YIG) single crystal at the
+cryogenic temperature $T$ as low as 2 K based on a RuO$_2$$-$AlO$_x$ on-chip
+thermometer film. By means of a reactive co-sputtering technique, we
+successfully fabricated RuO$_2$$-$AlO$_x$ films having a large temperature
+coefficient of resistance (TCR) of $\sim 100\% ~\textrm{K}^{-1}$ at around
+$2~\textrm{K}$. By using the RuO$_2$$-$AlO$_x$ film as an on-chip temperature
+sensor for a Pt/YIG device, we observe a SPE-induced temperature change on the
+order of sub-$\mu \textrm{K}$, the sign of which is reversed with respect to
+the external magnetic field $B$ direction. We found that the SPE signal
+gradually decreases and converges to zero by increasing $B$ up to
+$10~\textrm{T}$. The result is attributed to the suppression of magnon
+excitations due to the Zeeman-gap opening in the magnon dispersion of YIG,
+whose energy much exceeds the thermal energy at 2 K.",2311.01711v1
+2024-03-10,Spin Waves and Spin Currents in Magnon-Phonon Composite Resonator Induced by Acoustic Waves of Various Polarizations,"In this work, we present the results of a systematic experimental study of
+linear and parametric spin wave resonant excitation accompanied by spin
+currents (spin pumping) in a multifrequency composite bulk acoustic wave
+resonator with a ZnO-YIG-GGG-YIG/Pt structure. The features of magnetic
+dynamics excitation in YIG films due to magnetoelastic coupling with acoustic
+thickness modes of various polarizations are studied. Acoustic spin waves and
+spin pumping are detected by simultaneous frequency-field mapping of the
+inverse spin Hall effect voltage and the resonant frequencies of thickness
+extensional modes. In the parametric range of frequencies and fields, acoustic
+spin pumping induced by both shear and longitudinal polarization modes was
+observed. Linear acoustic spin waves are excited only by shear thickness
+extensional modes because longitudinal acoustic waves do not couple with the
+magnetic subsystem in linear regime.",2403.06274v1
+2021-04-21,Atomic Layer Deposition of Yttrium Iron Garnet Thin Films for 3D Magnetic Structures,"A wide variety of new phenomena such as novel magnetization configurations
+have been predicted to occur in three dimensional magnetic nanostructures.
+However, the fabrication of such structures is often challenging due to the
+specific shapes required, such as magnetic tubes and spirals. Furthermore, the
+materials currently used to assemble these structures are predominantly
+magnetic metals that do not allow to study the magnetic response of the system
+separately from the electronic one. In the field of spintronics, the
+prototypical material used for such experiments is the ferrimagnetic insulator
+yttrium iron garnet (Y$_3$Fe$_5$O$_{12}$, YIG). YIG is one of the best
+materials especially for magnonic studies due to its low Gilbert damping. Here,
+we report the first successful fabrication of YIG thin films via atomic layer
+deposition. To that end we utilize a supercycle approach based on the
+combination of sub-nanometer thin layers of the binary systems Fe$_2$O$_3$ and
+Y$_2$O$_3$ in the correct atomic ratio on Y$_3$Al$_5$O$_{12}$ substrates with a
+subsequent annealing step. Our process is robust against typical growth-related
+deviations, ensuring a good reproducibility. The ALD-YIG thin films exhibit a
+good crystalline quality as well as magnetic properties comparable to other
+deposition techniques. One of the outstanding characteristics of atomic layer
+deposition is its ability to conformally coat arbitrarily-shaped substrates.
+ALD hence is the ideal deposition technique to grant an extensive freedom in
+choosing the shape of the magnetic system. The atomic layer deposition of YIG
+enables the fabrication of novel three dimensional magnetic nanostructures,
+which in turn can be utilized for experimentally investigating the phenomena
+predicted in those structures.",2104.10293v2
+2014-08-25,Measurements of the exchange stiffness of YIG films by microwave resonance techniques,"Measurements of the exchange stiffness $D$ and the exchange constant $A$ of
+Yttrium Iron Garnet (YIG) films are presented. The YIG films with thicknesses
+from 0.9 $\mu$m to 2.6 $\mu$m were investigated with a microwave setup in a
+wide frequency range from 5 to 40 GHz. The measurements were performed when the
+external static magnetic field was applied in-plane and out-of-plane. The
+method of Schreiber and Frait, based on the analysis of the perpendicular
+standing spin wave (PSSW) mode frequency dependence on the applied out-of-plane
+magnetic field, was used to obtain the exchange stiffness $D$. This method was
+modified to avoid the influence of internal magnetic fields during the
+determination of the exchange stiffness. Furthermore, the method was adapted
+for in-plane measurements as well. The results obtained using all methods are
+compared and values of $D$ between $(5.18\pm0.01) \cdot 10^{-17}$T$\cdot$m$^2$
+and $(5.34\pm0.02) \cdot 10^{-17}$ T$\cdot$m$^2$ were obtained for different
+thicknesses. From this the exchange constant was calculated to be $A=(3.65 \pm
+0.38)~$pJ/m.",1408.5772v1
+2014-11-12,Magnonic Holographic Memory: from Proposal to Device,"In this work, we present recent developments in magnonic holographic memory
+devices exploiting spin waves for information transfer. The devices comprise a
+magnetic matrix and spin wave generating/detecting elements placed on the edges
+of the waveguides. The matrix consists of a grid of magnetic waveguides
+connected via cross junctions. Magnetic memory elements are incorporated within
+the junction while the read-in and read-out is accomplished by the spin waves
+propagating through the waveguides. We present experimental data on spin wave
+propagation through NiFe and YIG magnetic crosses. The obtained experimental
+data show prominent spin wave signal modulation (up to 20 dB for NiFe and 35 dB
+for YIG) by the external magnetic field, where both the strength and the
+direction of the magnetic field define the transport between the cross arms. We
+also present experimental data on the 2-bit magnonic holographic memory built
+on the double cross YIG structure with micro-magnets placed on the top of each
+cross. It appears possible to recognize the state of each magnet via the
+interference pattern produced by the spin waves with all experiments done at
+room temperature. Magnonic holographic devices aim to combine the advantages of
+magnetic data storage with wave-based information transfer. We present
+estimates on the spin wave holographic devices performance, including power
+consumption and functional throughput. According to the estimates, magnonic
+holographic devices may provide data processing rates higher than 10^18
+bits/cm2/s while consuming 0.15uW. Technological challenges and fundamental
+physical limits of this approach are also discussed.",1411.3388v1
+2015-04-10,Long range pure magnon spin diffusion observed in a non-local spin-Seebeck geometry,"The spin diffusion length for thermally excited magnon spins is measured by
+utilizing a non-local spin-Seebeck effect measurement. In a bulk single crystal
+of yttrium iron garnet (YIG) a focused laser thermally excites magnon spins.
+The spins diffuse laterally and are sampled using a Pt inverse spin Hall effect
+detector. Thermal transport modeling and temperature dependent measurements
+demonstrate the absence of spurious temperature gradients beneath the Pt
+detector and confirm the non-local nature of the experimental geometry.
+Remarkably, we find that thermally excited magnon spins in YIG travel over 120
+$\mu$m at 23 K, indicating that they are robust against inelastic scattering.
+The spin diffusion length is found to be at least 47 $\mu$m and as high as 73
+$\mu$m at 23 K in YIG, while at room temperature it drops to less than 10
+$\mu$m. Based on this long spin diffusion length, we envision the development
+of thermally powered spintronic devices based on electrically insulating, but
+spin conducting materials.",1504.02808v2
+2015-06-19,Origin of the thickness-dependent low-temperature enhancement of spin Seebeck effect in YIG films,"The temperature dependent longitudinal spin Seebeck effect (SSE) in heavy
+metal (HM)/ Y3Fe5O12 (YIG) bilayers is investigated as a function of different
+magnetic field strength, different HM detection material, and YIG thickness
+ranging from nm to mm. A large enhancement of the SSE signal is observed at low
+temperatures leading to a peak of the signal amplitude. We demonstrate that
+this enhancement shows a clear dependence on the film thickness, being more
+pronounced for thicker films and vanishing for films thinner than 600 nm. The
+peak temperature depends on the applied magnetic field strength as well as on
+the detection material and interface, revealing a more complex behavior beyond
+the currently discussed phonon-magnon coupling mechanism that considers only
+bulk effects. While the thickness dependence and magnetic field dependence can
+be well explained in the framework of the magnon-driven SSE by taking into
+account the frequency dependent propagation length of thermally excited magnons
+in the bulk material, the temperature dependence of the SSE is significantly
+influenced by the interface coupling to an adjacent detection layer. This
+indicates that previously neglected interface effects play a key role and that
+the spin current traversing the interface and being detected in the HM depends
+differently on the magnon frequency for different HMs.",1506.06037v1
+2015-08-30,Spin-transfer torque based damping control of parametrically excited spin waves in a magnetic insulator,"The damping of spin waves parametrically excited in the magnetic insulator
+Yttrium Iron Garnet (YIG) is controlled by a dc current passed through an
+adjacent normal-metal film. The experiment is performed on a macroscopically
+sized YIG(100nm)/Pt(10nm) bilayer of 4x2 mm^2 lateral dimensions. The spin-wave
+relaxation frequency is determined via the threshold of the parametric
+instability measured by Brillouin light scattering (BLS) spectroscopy. The
+application of a dc current to the Pt film leads to the formation of a
+spin-polarized electron current normal to the film plane due to the spin Hall
+effect (SHE). This spin current exerts a spin transfer torque (STT) in the YIG
+film and, thus, changes the spin-wave damping. Depending on the polarity of the
+applied dc current with respect to the magnetization direction, the damping can
+be increased or decreased. The magnitude of its variation is proportional to
+the applied current. A variation in the relaxation frequency of +/-7.5% is
+achieved for an applied dc current density of 5*10^10 A/m^2.",1508.07517v1
+2015-12-03,Cavity quantum electrodynamics with ferromagnetic magnons in a small yttrium-iron-garnet sphere,"Hybridizing collective spin excitations and a cavity with high cooperativity
+provides a new research subject in the field of cavity quantum electrodynamics
+and can also have potential applications to quantum information. Here we report
+an experimental study of cavity quantum electrodynamics with ferromagnetic
+magnons in a small yttrium-iron-garnet (YIG) sphere at both cryogenic and room
+temperatures. We observe for the first time a strong coupling of the same
+cavity mode to both a ferromagnetic-resonance (FMR) mode and a magnetostatic
+(MS) mode near FMR in the quantum limit. This is achieved at a temperature ~ 22
+mK, where the average microwave photon number in the cavity is less than one.
+At room temperature, we also observe strong coupling of the cavity mode to the
+FMR mode in the same YIG sphere and find a slight increase of the damping rate
+of the FMR mode. These observations reveal the extraordinary robustness of the
+FMR mode against temperature. However, the MS mode becomes unobservable at room
+temperature in the measured transmission spectrum of the microwave cavity
+containing the YIG sphere. Our numerical simulations show that this is due to a
+drastic increase of the damping rate of the MS mode.",1512.00983v1
+2017-01-25,Hybrid nanodiamond-YIG systems for efficient quantum information processing and nanoscale sensing,"The nitrogen-vacancy (NV) center in diamond has been extensively studied in
+recent years for its remarkable quantum coherence properties that make it an
+ideal candidate for room temperature quantum computing and quantum sensing
+schemes. However, these schemes rely on spin-spin dipolar interactions, which
+require the NV centers to be within a few nanometers from each other while
+still separately addressable, or to be in close proximity of the diamond
+surface, where their coherence properties significantly degrade. Here we
+demonstrate a method for overcoming these limitations using a hybrid yttrium
+iron garnet (YIG)-nanodiamond quantum system constructed with the help of
+directed assembly and transfer printing techniques. We show that YIG spin-waves
+can amplify the oscillating field of a microwave source by more than two orders
+of magnitude and efficiently mediate its coherent interactions with an NV
+center ensemble. These results demonstrate that spin-waves in ferromagnets can
+be used as quantum buses for enhanced, long-range qubit interactions, paving
+the way to ultra-efficient manipulation and coupling of solid state defects in
+hybrid quantum networks and sensing devices.",1701.07401v1
+2017-09-30,Tuning the diffusion of magnon in Y3Fe5O12 by light excitation,"Deliberate control of magnon transportation will lead to an energy-efficient
+technology for information transmission and processing. Y3Fe5O12(YIG),
+exhibiting extremely large magnon diffusion length due to the low magnetic
+damping constant, has been intensively investigated for decades. While most of
+the previous works focused on the determination of magnon diffusion length by
+various techniques, herein we demonstrated how to tune magnon diffusion by
+light excitation. We found that the diffusion length of thermal magnons is
+strongly dependent on light wavelength when the magnon is generated by exposing
+YIG directly to laser beam. The diffusion length, determined by a nonlocal
+geometry at room temperature, is ~30 um for the magnons produced by visible
+light (400-650 nm), and ~136-156 um for the laser between 808 nm and 980 nm.
+The diffusion distance is much longer than the reported value. In addition to
+thermal gradient, we found that light illumination affected the electron
+configuration of the Fe3+ ion in YIG. Long wavelength laser triggers a high
+spin to low spin state transition of the Fe3+ ions in FeO6 octahedron. This in
+turn causes a substantial softening of the magnon thus a dramatic increase in
+diffusion distance. The present work paves the way towards an efficient tuning
+of magnon transport behavior which is crucially important for magnon
+spintronics.",1710.00222v2
+2017-12-09,Observation of spin-orbit magnetoresistance in metallic thin films on magnetic insulators,"A magnetoresistance effect induced by the Rashba spin-orbit interaction was
+predicted, but not yet observed, in bilayers consisting of normal metal and
+ferromagnetic insulator. Here, we present an experimental observation of this
+new type of spin-orbit magnetoresistance (SOMR) effect in a bilayer structure
+Cu[Pt]/Y3Fe5O12 (YIG), where the Cu/YIG interface is decorated with nanosize Pt
+islands. This new MR is apparently not caused by the bulk spin-orbit
+interaction because of the negligible spin-orbit interaction in Cu and the
+discontinuity of the Pt islands. This SOMR disappears when the Pt islands are
+absent or located away from the Cu/YIG interface, therefore we can
+unambiguously ascribe it to the Rashba spin-orbit interaction at the interface
+enhanced by the Pt decoration. The numerical Boltzmann simulations are
+consistent with the experimental SOMR results in the angular dependence of
+magnetic field and the Cu thickness dependence. Our finding demonstrates the
+realization of the spin manipulation by interface engineering.",1712.03322v1
+2018-01-20,Magnon Valve Effect Between Two Magnetic Insulators,"The key physics of the spin valve involves spin-polarized conduction
+electrons propagating between two magnetic layers such that the device
+conductance is controlled by the relative magnetization orientation of two
+magnetic layers. Here, we report the effect of a magnon valve which is made of
+two ferromagnetic insulators (YIG) separated by a nonmagnetic spacer layer
+(Au). When a thermal gradient is applied perpendicular to the layers, the
+inverse spin Hall voltage output detected by a Pt bar placed on top of the
+magnon valve depends on the relative orientation of the magnetization of two
+YIG layers, indicating the magnon current induced by spin Seebeck effect at one
+layer affects the magnon current in the other layer separated by Au. We
+interpret the magnon valve effect by the angular momentum conversion and
+propagation between magnons in two YIG layers and conduction electrons in the
+Au layer. The temperature dependence of magnon valve ratio shows approximately
+a power law, supporting the above magnon-electron spin conversion mechanism.
+This work opens a new class of valve structures beyond the conventional spin
+valves.",1801.06617v2
+2018-10-28,Magnetic Resonance in Defect Spins mediated by Spin Waves,"In search of two level quantum systems that implement a qubit, the
+nitrogen-vacancy (NV) center in diamond has been intensively studied for years.
+Despite favorable properties such as remarkable defect spin coherence times,
+the addressability of NV centers raises some technical issues. The coupling of
+a single NV center to an external driving field is limited to short distances,
+since an efficient coupling requires the NV to be separated by only a few
+microns away from the source. As a way to overcome this problem, an enhancement
+of coherent coupling between NV centers and a microwave field has recently been
+experimentally demonstrated using spin waves propagating in an adjacent yttrium
+iron garnet (YIG) film [1]. In this paper we analyze the optically detected
+magnetic resonance spectra that arise when an NV center is placed on top of a
+YIG film for a geometry similar to the one in the experiment. We analytically
+calculate the oscillating magnetic field of the spin wave on top of the YIG
+surface to determine the coupling of spin waves to the NV center. We compare
+this coupling to the case when the spin waves are absent and the NV center is
+driven only with the antenna field and show that the calculated coupling
+enhancement is dramatic and agrees well with the one obtained in the recent
+experiment.",1810.11841v1
+2018-12-02,Direct detection of induced magnetic moment and efficient spin-to-charge conversion in graphene/ferromagnetic structures,"This article shows that the spin-to-charge current conversion in single-layer
+graphene (SLG) by means of the inverse Rashba-Edelstein effect (IREE) is made
+possible with the integration of this remarkable 2D-material with the unique
+ferrimagnetic insulator yttrium iron garnet (YIG = $Y_{3}Fe_{5}O_{12}$) as well
+as with the ferromagnetic metal permalloy (Py = $Ni_{81}Sb_{19}$). By means of
+X-ray absorption spectroscopy (XAS) and magnetic circular dichroism (XMCD)
+techniques, we show that the carbon atoms of the SLG acquires an induced
+magnetic moment due to the proximity effect with the magnetic layer. The spin
+currents are generated in the magnetic layer by spin pumping from microwave
+driven ferromagnetic resonance and are detected by a dc voltage along the
+graphene layer, at room temperature. The spin-to-charge current conversion,
+occurring at the graphene layer, is explained by the extrinsic spin-orbit
+interaction (SOI) induced by the proximity effect with the ferromagnetic layer.
+The results obtained for the SLG/YIG and SLG/Py systems confirm very similar
+values for the IREE parameter, which are larger than the values reported in
+previous studies for SLG. We also report systematic investigations of the
+electronic and magnetic properties of the SLG/YIG by means of scanning
+tunneling microscopy (STM).",1812.00455v1
+2019-12-22,First-principles study of magnon-phonon interactions in gadolinium iron garnet,"We obtained the spin-wave spectrum based on a first-principles method of
+exchange constants, calculated the phonon spectrum by the first-principles
+phonon calculation method, and extracted the broadening of the magnon spectrum,
+$\Delta \omega$, induced by magnon-phonon interactions in gadolinium iron
+garnet (GdIG). Using the obtained exchange constants, we reproduce the
+experimental Curie temperature and the compensation temperature from spin
+models using Metropolis Monte Carlo (MC) simulations. In the lower-frequency
+regime, the fitted positions of the magnon-phonon dispersion crossing points
+are consistent with the inelastic neutron scattering experiment. We found that
+the $\Delta \omega$ and magnon wave vector $k$ have a similar relationship in
+YIG. The broadening of the acoustic spin-wave branch is proportional to
+$k^{2}$, while that of the YIG-like acoustic branch and the optical branch are
+a constant. At a specific $k$, the magnon-phonon thermalization time of
+$\tau_{mp}$ are approximately $10^{-9}$~s, $10^{-13}$~s, and $10^{-14}$~s for
+acoustic branch, YIG-like acoustic branch, and optical branch, respectively.
+This research provides specific and effective information for developing a
+clear understanding of the spin-wave mediated spin Seebeck effect and
+complements the lack of lattice dynamics calculations of GdIG.",1912.10432v1
+2020-02-19,Manipulation of coupling and magnon transport in magnetic metal-insulator hybrid structures,"Ferromagnetic metals and insulators are widely used for generation, control
+and detection of magnon spin signals. Most magnonic structures are based
+primarily on either magnetic insulators or ferromagnetic metals, while
+heterostructures integrating both of them are less explored. Here, by
+introducing a Pt/yttrium iron garnet (YIG)/permalloy (Py) hybrid structure
+grown on Si substrate, we studied the magnetic coupling and magnon transmission
+across the interface of the two magnetic layers. We found that within this
+structure, Py and YIG exhibit an antiferromagnetic coupling field as strong as
+150 mT, as evidenced by both the vibrating-sample magnetometry and polarized
+neutron reflectometry measurements. By controlling individual layer thicknesses
+and external fields, we realize parallel and antiparallel magnetization
+configurations, which are further utilized to control the magnon current
+transmission. We show that a magnon spin valve with an ON/OFF ratio of ~130%
+can be realized out of this multilayer structure at room temperature through
+both spin pumping and spin Seebeck effect experiments. Thanks to the efficient
+control of magnon current and the compatibility with Si technology, the
+Pt/YIG/Py hybrid structure could potentially find applications in magnon-based
+logic and memory devices.",2002.08266v1
+2022-03-20,Deposition temperature dependence of thermo-spin and magneto-thermoelectric conversion in Co$_2$MnGa films on Y$_3$Fe$_5$O$_{12}$ and Gd$_3$Ga$_5$O$_{12}$,"We have characterized Co$_2$MnGa (CMG) Heusler alloy films grown on
+Y$_3$Fe$_5$O$_{12}$ (YIG) and Gd$_3$Ga$_5$O$_{12}$ (GGG) substrates at
+different deposition temperatures and investigated thermo-spin and
+magneto-thermoelectric conversion properties by means of a lock-in thermography
+technique. X-ray diffraction, magnetization, and electrical transport
+measurements show that the deposition at high substrate temperatures induces
+the crystallized structures of CMG while the resistivity of the CMG films on
+YIG (GGG) prepared at and above 500 {\deg}C (550 {\deg}C) becomes too high to
+measure the thermo-spin and magneto-thermoelectric effects due to large
+roughness, highlighting the difficulty of fabricating highly ordered continuous
+CMG films on garnet structures. Our lock-in thermography measurements show that
+the deposition at high substrate temperatures results in an increase in the
+current-induced temperature change for CMG/GGG and a decrease in that for
+CMG/YIG. The former indicates the enhancement of the anomalous Ettingshausen
+effect in CMG through crystallization. The latter can be explained by the
+superposition of the anomalous Ettingshausen effect and the spin Peltier effect
+induced by the positive (negative) charge-to-spin conversion for the amorphous
+(crystallized) CMG films. These results provide a hint to construct
+spin-caloritronic devices based on Heusler alloys.",2203.10566v2
+2022-05-27,Magnonic Casimir Effect in Ferrimagnets,"Quantum fluctuations are the key concepts of quantum mechanics. Quantum
+fluctuations of quantum fields induce a zero-point energy shift under spatial
+boundary conditions. This quantum phenomenon, called the Casimir effect, has
+been attracting much attention beyond the hierarchy of energy scales, ranging
+from elementary particle physics to condensed matter physics together with
+photonics. However, the application of the Casimir effect to spintronics has
+not yet been investigated enough, particularly to ferrimagnetic thin films,
+although yttrium iron garnet (YIG) is one of the best platforms for
+spintronics. Here we fill this gap. Using the lattice field theory, we
+investigate the Casimir effect induced by quantum fields for magnons in
+insulating magnets and find that the magnonic Casimir effect can arise not only
+in antiferromagnets but also in ferrimagnets including YIG thin films. Our
+result suggests that YIG, the key ingredient of magnon-based spintronics, can
+serve also as a promising platform for manipulating and utilizing Casimir
+effects, called Casimir engineering. Microfabrication technology can control
+the thickness of thin films and realize the manipulation of the magnonic
+Casimir effect. Thus, we pave the way for magnonic Casimir engineering.",2205.13802v3
+2022-06-30,Experimental Demonstration of a Spin-Wave Lens Designed with Machine Learning,"We present the design and experimental realization of a device that acts like
+a spin-wave lens i.e., it focuses spin waves to a specified location. The
+structure of the lens does not resemble any conventional lens design, it is a
+nonintuitive pattern produced by a machine learning algorithm. As a spin-wave
+design tool, we used our custom micromagnetic solver ""SpinTorch"" that has
+built-in automatic gradient calculation and can perform backpropagation through
+time for spin-wave propagation. The training itself is performed with the
+saturation magnetization of a YIG film as a variable parameter, with the goal
+to guide spin waves to a predefined location. We verified the operation of the
+device in the widely used mumax3 micromagnetic solver, and by experimental
+realization. For the experimental implementation, we developed a technique to
+create effective saturation-magnetization landscapes in YIG by direct
+focused-ion-beam irradiation. This allows us to rapidly transfer the nanoscale
+design patterns to the YIG medium, without patterning the material by etching.
+We measured the effective saturation magnetization corresponding to the FIB
+dose levels in advance and used this mapping to translate the designed
+scatterer to the required dose levels. Our demonstration serves as a proof of
+concept for a workflow that can be used to realize more sophisticated spin-wave
+devices with complex functionality, e.g., spin-wave signal processors, or
+neuromorphic devices.",2207.00055v1
+2022-09-01,Growth parameters of Bi0.1Y2.9Fe5O12 thin films for high frequency applications,"The growth and characterization of Bismuth (Bi) substituted YIG (Bi-YIG,
+Bi0.1Y2.9Fe5O12) thin films are reported. Pulsed laser deposited (PLD) films
+with thicknesses ranging from 20 to 150 nm were grown on Gadolinium Gallium
+Garnet substrates. Two substrate orientations of (100) and (111) were
+considered. The enhanced distribution of Bi3+ ions at dodecahedral site along
+(111) is observed to lead to an increment in lattice constant from 12.379
+angstrom in (100) to 12.415 angstrom in (111) oriented films. Atomic force
+microscopy images showed decreasing roughness with increasing film thickness.
+Compared to (100) grown films, (111) oriented films showed an increase in
+ferromagnetic resonance linewidth and consequent increase in Gilbert damping.
+The lowest Gilbert damping values are found to be (1.06) * 10E-4 for (100) and
+(2.30) * 10E-4 for (111) oriented films with thickness of 150 nm. The observed
+values of extrinsic linewidth, effective magnetization, and anisotropic field
+are related to thickness of the films and substrate orientation. In addition,
+the in-plane angular variation established four-fold symmetry for the (100)
+deposited films unlike the case of (111) deposited films. This study prescribes
+growth conditions for PLD grown single-crystalline Bi-YIG films towards desired
+high frequency and magneto-optical device applications.",2209.00558v1
+2022-09-05,Nonlocal detection of interlayer three-magnon coupling,"A leading nonlinear effect in magnonics is the interaction that splits a
+high-frequency magnon into two low-frequency ones with conserved linear
+momentum. Here, we report experimental observation of nonlocal three-magnon
+scattering between spatially separated magnetic systems, viz. a CoFeB nanowire
+and an yttrium iron garnet (YIG) thin film. Above a certain threshold power of
+an applied microwave field, a CoFeB Kittel magnon splits into a pair of
+counter-propagating YIG magnons that induce voltage signals in Pt electrodes on
+each side, in excellent agreement with model calculations based on the
+interlayer dipolar interaction. The excited YIG magnon pairs reside mainly in
+the first excited (n=1) perpdendicular standing spin-wave mode. With increasing
+power, the n=1 magnons successively scatter into nodeless (n=0) magnons through
+a four-magnon process. Our results help to assess non-local scattering
+processes in magnonic circuits that may enable quantum entanglement between
+distant magnons for quantum information applications.",2209.01875v1
+2022-12-05,Propagating spin-wave spectroscopy in nanometer-thick YIG films at millikelvin temperatures,"Performing propagating spin-wave spectroscopy of thin films at millikelvin
+temperatures is the next step towards the realisation of large-scale integrated
+magnonic circuits for quantum applications. Here we demonstrate spin-wave
+propagation in a $100\,\mathrm{nm}$-thick yttrium-iron-garnet film at the
+temperatures down to $45 \,\mathrm{mK}$, using stripline nanoantennas deposited
+on YIG surface for the electrical excitation and detection. The clear
+transmission characteristics over the distance of $10\,\mu \mathrm{m}$ are
+measured and the subtracted spin-wave group velocity and the YIG saturation
+magnetisation agree well with the theoretical values. We show that the
+gadolinium-gallium-garnet substrate influences the spin-wave propagation
+characteristics only for the applied magnetic fields beyond $75\,\mathrm{mT}$,
+originating from a GGG magnetisation up to $47 \,\mathrm{kA/m}$ at $45
+\,\mathrm{mK}$. Our results show that the developed fabrication and measurement
+methodologies enable the realisation of integrated magnonic quantum
+nanotechnologies at millikelvin temperatures.",2212.02257v3
+2023-01-31,Complete identification of spin-wave eigenmodes excited by parametric pumping in YIG microdisks,"We present the parametric excitation of spin-wave modes in YIG micro-disks
+via parallel pumping. Their spectroscopy is performed using magnetic resonance
+force microscopy (MRFM), while their spatial profiles are determined by
+micro-focus Brillouin light scattering (BLS). We observe that almost all the
+fundamental eigenmodes of an in-plane magnetized YIG micro-disk, calculated
+using a micromagnetic eigenmode solver, can be excited using the parallel
+pumping scheme, as opposed to the transverse one. The comparison between the
+MRFM and BLS data on one side, and the simulations on the other side, provides
+the complete spectroscopic labeling of over 40 parametrically excited modes.
+Our findings could be promising for spin-wave-based computation schemes, in
+which the amplitudes of a large number of spin-wave modes have to be
+controlled.",2301.13468v1
+2023-02-01,Temperature-independent ferromagnetic resonance shift in Bi-doped YIG garnets through magnetic anisotropy tuning,"Thin garnet films are becoming central for magnon-spintronics and
+spin-orbitronics devices as they show versatile magnetic properties together
+with low magnetic losses. These fields would benefit from materials in which
+heat does not affect the magnetization dynamics, an effect known as the
+non-linear thermal frequency shift. In this study, low damping Bi substituted
+Iron garnet (Bi:YIG) ultra-thin films have been grown using Pulsed Laser
+Deposition. Through a fine tuning of the growth parameters, the precise control
+of the perpendicular magnetic anisotropy allows to achieve a full compensation
+of the dipolar magnetic anisotropy. Strikingly, once the growth conditions are
+optimized, varying the growth temperature from 405 {\deg}C to 475 {\deg}C as
+the only tuning parameter induces the easy-axis to go from out-of-plane to
+in-plane. For films that are close to the dipolar compensation, Ferromagnetic
+Resonance measurements yield an effective magnetization $\mu _{0}M_{eff} (T)$
+that has almost no temperature dependence over a large temperature range (260 K
+to 400 K) resulting in an anisotropy temperature exponent of 2. These findings
+put Bi:YIG system among the very few materials in which the temperature
+dependence of the magnetic anisotropy varies at the same rate than the
+saturation magnetization. This interesting behavior is ascribed
+phenomenologically to the sizable orbital moment of $Bi^{3+}$.",2302.00585v1
+2015-04-07,Generation of coherent spin-wave modes in Yttrium Iron Garnet microdiscs by spin-orbit torque,"Spin-orbit effects [1-4] have the potential of radically changing the field
+of spintronics by allowing transfer of spin angular momentum to a whole new
+class of materials. In a seminal letter to Nature [5], Kajiwara et al. showed
+that by depositing Platinum (Pt, a normal metal) on top of a 1.3 $\mu$m thick
+Yttrium Iron Garnet (YIG, a magnetic insulator), one could effectively transfer
+spin angular momentum through the interface between these two different
+materials. The outstanding feature was the detection of auto-oscillation of the
+YIG when enough dc current was passed in the Pt. This finding has created a
+great excitement in the community for two reasons: first, one could control
+electronically the damping of insulators, which can offer improved properties
+compared to metals, and here YIG has the lowest damping known in nature;
+second, the damping compensation could be achieved on very large objects, a
+particularly relevant point for the field of magnonics [6,7] whose aim is to
+use spin-waves as carriers of information. However, the degree of coherence of
+the observed auto-oscillations has not been addressed in ref. [5]. In this
+work, we emphasize the key role of quasi-degenerate spin-wave modes, which
+increase the threshold current. This requires to reduce both the thickness and
+lateral size in order to reach full damping compensation [8] , and we show
+clear evidence of coherent spin-orbit torque induced auto-oscillation in
+micron-sized YIG discs of thickness 20 nm.",1504.01512v1
+2018-03-02,Long lifetime of thermally-excited magnons in bulk yttrium iron garnet,"Spin currents are generated within the bulk of magnetic materials due to heat
+flow, an effect called intrinsic spin-Seebeck. This bulk bosonic spin current
+consists of a diffusing thermal magnon cloud, parametrized by the magnon
+chemical potential ($\mu_{m}$), with a diffusion length of several microns in
+yttrium iron garnet (YIG). Transient opto-thermal measurements of the
+spin-Seebeck effect (SSE) as a function of temperature reveal the time
+evolution of $\mu_{m}$ due to intrinsic SSE in YIG. The interface SSE develops
+at times < 2 ns while the intrinsic SSE signal continues to evolve at times >
+500 $\mu$s, dominating the temperature dependence of SSE in bulk YIG.
+Time-dependent SSE data are fit to a multi-temperature model of coupled
+spin/heat transport using finite element method (FEM), where the magnon spin
+lifetime ($\tau$) and magnon-phonon thermalization time ($\tau_{mp}$) are used
+as fit parameters. From 300 K to 4 K, $\tau_{mp}$ varies from 1 to 10 ns,
+whereas $\tau$ varies from 2 to 60 $\mu$s with the spin lifetime peaking at 90
+K. At low temperature, a reduction in $\tau$ is observed consistent with
+impurity relaxation reported in ferromagnetic resonance measurements. These
+results demonstrate that the thermal magnon cloud in YIG contains extremely low
+frequency magnons (~10 GHz) providing spectral insight to the microscopic
+scattering processes involved in magnon spin/heat diffusion.",1803.01054v3
+2018-05-07,Detection of the interfacial exchange field at a ferromagnetic insulator-nonmagnetic metal interface with pure spin currents,"At the interface between a nonmagnetic metal (NM) and a ferromagnetic
+insulator (FI) spin current can interact with the magnetization, leading to a
+modulation of the spin current. The interfacial exchange field at these FI-NM
+interfaces can be probed by placing the interface in contact with the spin
+transport channel of a lateral spin valve (LSV) device and observing additional
+spin relaxation processes. We study interfacial exchange field in lateral spin
+valve devices where Cu spin transport channel is in proximity with
+ferromagnetic insulator EuS (EuS-LSV) and yttrium iron garnet
+Y$_3$Fe$_5$O$_{12}$ (YIG-LSV). The spin signals were compared with reference
+lateral spin valve devices fabricated on nonmagnetic Si/SiO$_2$ substrate with
+MgO or AlO$_x$ capping. The nonlocal spin valve signal is about 4 and 6 times
+lower in the EuS-LSV and YIG-LSV, respectively. The suppression in the spin
+signal has been attributed to enhanced surface spin-flip probability at the
+Cu-EuS (or Cu-YIG) interface due to interfacial spin-orbit field. Besides spin
+signal suppression we also found widely observed low temperature peak in the
+spin signal at $T \sim$30 K is shifted to higher temperature in the case of
+devices in contact with EuS or YIG. Temperature dependence of spin signal for
+different injector-detector distances reveal fluctuating exchange field at
+these interfaces cause additional spin decoherence which limit spin relaxation
+time in addition to conventional sources of spin relaxation. Our results show
+that temperature dependent measurement with pure spin current can be used to
+probe interfacial exchange field at the ferromagnetic insulator-nonmagnetic
+metal interface.",1805.02433v2
+2019-05-10,Experimental Implementations of Cavity-Magnon Systems: from Ultra Strong Coupling to Applications in Precision Measurement,"Several experimental implementations of cavity-magnon systems are presented.
+First an Yttrium Iron Garnet (YIG) block is placed inside a re-entrant cavity
+where the resulting hybrid mode is measured to be in the ultra strong coupling
+regime. When fully hybridised the ratio between the coupling rate and uncoupled
+mode frequencies is determined to be $g/\omega=0.46$. Next a thin YIG cylinder
+is placed inside a loop gap cavity. The bright mode of this cavity couples to
+the YIG sample and is similarly measured to be in the ultra strong coupling
+regime with ratio of coupling rate to uncoupled mode frequencies as
+$g/\omega=0.34$. A larger spin density medium such as lithium ferrite (LiFe) is
+expected to improve couplings by a factor of 1.46 in both systems as coupling
+strength is shown to be proportional to the square root of spin density and
+magnetic moment. Such strongly coupled systems are potentially useful for
+cavity QED, hybrid quantum systems and precision dark matter detection
+experiments. The YIG disc in the loop gap cavity, is, in particular, shown to
+be a strong candidate for dark matter detection. Finally, a LiFe sphere inside
+a two post re-entrant cavity is considered. In past work it was shown that the
+magnon mode in the sample has a turnover point in frequency. Additionally, it
+was predicted that if the system was engineered such that it fully hybridised
+at this turnover point the cavity-magnon polariton (CMP) transition frequency
+would become insensitive to both first and second order magnetic bias field
+fluctuations, a result useful for precision frequency applications. This work
+implements such a system by engineering the cavity mode frequency to near this
+turnover point, with suppression in sensitivity to second order bias magnetic
+field fluctuations shown.",1905.04002v2
+2020-08-21,"Macroscopic, layered onion shell like magnetic domain structure generated in YIG film using ultrashort, megagauss magnetic pulses","Study of the formation and evolution of large scale, ordered structures is an
+enduring theme in science. The generation, evolution and control of large sized
+magnetic domains are intriguing and challenging tasks, given the complex nature
+of competing interactions present in any magnetic system. Here, we demonstrate
+large scale non-coplanar ordering of spins, driven by picosecond, megagauss
+magnetic pulses derived from a high intensity, femtosecond laser. Our studies
+on a specially designed Yttrium Iron Garnet (YIG)/dielectric/metal film
+sandwich target, show the creation of complex, large, concentric, elliptical
+shaped magnetic domains which resemble the layered shell structure of an onion.
+The largest shell has a major axis of over hundreds of micrometers, in stark
+contrast to conventional sub micrometer scale polygonal, striped or bubble
+shaped magnetic domains found in magnetic materials, or the large dumbbell
+shaped domains produced in magnetic films irradiated with accelerator based
+relativistic electron beams. Through micromagnetic simulations, we show that
+the giant magnetic field pulses create ultrafast terahertz (THz) spin waves. A
+snapshot of these fast propagating spin waves is stored as the layered onion
+shell shaped domains in the YIG film. Typically, information transport via spin
+waves in magnonic devices occurs in the gigahertz (GHz) regime, where the
+devices are susceptible to thermal disturbances at room temperature. Our
+intense laser light pulse - YIG sandwich target combination, paves the way for
+room temperature table-top THz spin wave devices, which operate just above or
+in the range of the thermal noise floor. This dissipation-less device offers
+ultrafast control of spin information over distances of few hundreds of
+microns.",2008.09473v1
+2022-10-08,One Analytical Approach of Rashba-Edelstein Magnetoresistance in 2D Materials,"We study analytically the Rashba-Edelstein magnetoresistance (REMR) in a
+structure made from an insulator ferromagnet, such as yttrium iron garnet
+(YIG), and a 2D material (2DM) with direct and inverse Rashba-Edelstein
+effects, such as SLG and MoS$_2$. Our results represent an efficient way of
+analyzing the Rashba-Edelstein effects.",2210.03854v1
+2023-08-14,Investigation of Phonon Lifetimes and Magnon-Phonon Coupling in YIG/GGG Hybrid Magnonic Systems in the Diffraction Limited Regime,"Quantum memories facilitate the storage and retrieval of quantum information
+for on-chip and long-distance quantum communications. Thus, they play a
+critical role in quantum information processing and have diverse applications
+ranging from aerospace to medical imaging fields. Bulk acoustic wave (BAW)
+phonons are one of the most attractive candidates for quantum memories because
+of their long lifetime and high operating frequency. In this work, we establish
+a modeling approach that can be broadly used to design hybrid magnonic
+high-overtone bulk acoustic wave resonator (HBAR) structures for high-density,
+long-lasting quantum memories and efficient quantum transduction devices. We
+illustrate the approach by investigating a hybrid magnonic system, where BAW
+phonons are excited in a gadolinium iron garnet (GGG) thick film via coupling
+with magnons in a patterned yttrium iron garnet (YIG) thin film. We present
+theoretical and numerical analyses of the diffraction-limited BAW phonon
+lifetimes, modeshapes, and their coupling strengths to magnons in planar and
+confocal YIG/GGG HBAR structures. We utilize Fourier beam propagation and
+Hankel transform eigenvalue problem methods and discuss the effectiveness of
+the two methods to predict the HBAR phonons. We discuss strategies to improve
+the phonon lifetimes, since increased lifetimes have direct implications on the
+storage times of quantum states for quantum memory applications. We find that
+ultra-high, diffraction-limited, cooperativities and phonon lifetimes on the
+order of ~10^5 and ~10 milliseconds, respectively, could be achieved using a
+CHBAR structure with 10mum lateral YIG dimension. Additionally, the confocal
+HBAR structure will offer more than 100-fold improvement of integration
+density. A high integration density of on-chip memory or transduction centers
+is naturally desired for high-density memory or transduction devices.",2308.06896v2
+2024-02-22,Laser patterning of magnonic structure via local crystallization of Yittrium Iron Garnet,"The fabrication and integration of high-quality structures of Yttrium Iron
+Garnet (YIG) is critical for magnonics.Films with excellent properties are
+obtained only on single crystal Gadolinium Gallium Garnet (GGG) substrates
+using high-temperature processes. The subsequent realization of magnonic
+structures via lithography and etching is not straightforward as it requires a
+tight control of the edge roughness, to avoid magnon scattering, and
+planarization in case of multilayer devices. In this work we describe a
+different approach based on local laser annealing of amorphous YIG films,
+avoiding the need for subjecting the entire sample to high thermal budgets and
+for physical etching. Starting from amorphous and paramagnetic YIG films grown
+by pulsed laser deposition at room temperature on GGG, a 405 nm laser is used
+for patterning arbitrary shaped ferrimagnetic structures by local
+crystallization. In thick films (160 nm) the laser induced surface corrugation
+prevents the propagation of spin-wave modes in patterned conduits. For thinner
+films (80 nm) coherent propagation is observed in 1.2 micron wide conduits
+displaying an attenuation length of 5 micron which is compatible with a damping
+coefficient of about 5e-3. Possible routes to achieve damping coefficients
+compatible with state-of-the art epitaxial YIG films are discussed.",2402.14444v1
+2005-04-22,Perturbation of magnetostatic modes observed by FMRFM,"Magnetostatic modes of Yttrium Iron Garnet (YIG) films are investigated by
+ferromagnetic resonance force microscopy (FMRFM). A thin film ``probe'' magnet
+at the tip of a compliant cantilever introduces a local inhomogeneity in the
+internal field of the YIG sample. This influences the shape of the sample's
+magnetostatic modes, thereby measurably perturbing the strength of the force
+coupled to the cantilever. We present a theoretical model that explains these
+observations; it shows that tip-induced variation of the internal field creates
+either a local ``potential barrier'' or ``potential well'' for the
+magnetostatic waves. The data and model together indicate that local magnetic
+imaging of ferromagnets is possible, even in the presence of long-range spin
+coupling, through the induction of localized magnetostatic modes predicted to
+arise from sufficiently strong tip fields.",0504598v1
+2009-03-17,Microscopic spin-wave theory for yttrium-iron garnet films,"Motivated by recent experiments on thin films of the ferromagnetic insulator
+yttrium-iron garnet (YIG), we have developed an efficient microscopic approach
+to calculate the spin-wave spectra of these systems. We model the
+experimentally relevant magnon band of YIG using an effective quantum
+Heisenberg model on a cubic lattice with ferromagnetic nearest neighbor
+exchange and long-range dipole-dipole interactions. After a bosonization of the
+spin degrees of freedom via a Holstein-Primakoff transformation and a
+truncation at quadratic order in the bosons, we obtain the spin-wave spectra
+for experimentally relevant parameters without further approximation by
+numerical diagonalization, using efficient Ewald summation techniques to carry
+out the dipolar sums. We compare our numerical results with two different
+analytic approximations and with predictions based on the phenomenological
+Landau-Lifshitz equation.",0903.2847v2
+2009-07-16,Reverse Doppler effect in backward spin waves scattered on acoustic waves,"We report on the observation of reverse Doppler effect in backward spin waves
+reflected off of surface acoustic waves. The spin waves are excited in a
+yttrium iron garnet (YIG) film. Simultaneously, acoustic waves are also
+generated. The strain induced by the acoustic waves in the magnetostrictive YIG
+film results in the periodic modulation of the magnetic anisotropy in the film.
+Thus, in effect, a travelling Bragg grating for the spin waves is produced. The
+backward spin waves reflecting off of this grating exhibit a reverse Doppler
+shift: shifting down rather than up in frequency when reflecting off of an
+approaching acoustic wave. Similarly, the spin waves are shifted up in
+frequency when reflecting from receding acoustic waves.",0907.2902v1
+2012-06-29,Platinum thickness dependence of the inverse spin-Hall voltage from spin pumping in a hybrid YIG/Pt system,"We show the first experimental observation of the platinum (Pt) thickness
+dependence in a hybrid YIG/Pt system of the inverse spin-Hall effect from spin
+pumping, over a large frequency range and for different rf powers. From the
+measurement of the dc voltage ($\Delta\textrm{V}$) at the resonant condition
+and the resistance ($R$) of the Pt layer, a strong enhancement of the ratio
+$\Delta\textrm{V}/R$ has been observed, which is not in agreement with previous
+studies on the NiFe/Pt system. The origin of this behaviour is still unclear
+and cannot be explained by the spin transport model that we have used.",1206.7080v1
+2012-08-03,Field-dependence of magnon decay in yttrium iron garnet thin films,"We discuss threshold field-dependence of the decay rate of the uniform magnon
+mode in yttrium iron garnet (YIG) thin films. We demonstrate that decays must
+cease to exist in YIG films of thickness less than 1 \mu m, the lengthscale
+defined by the exchange length. We show that due to the symmetry of the
+three-magnon coupling the decay rate is linear in \Delta H=(Hc-H) in the
+vicinity of the threshold field Hc instead of the step-like \Gamma
+\Theta(\Delta H) expected from the two-dimensional character of magnon
+excitations in such films. For thicker films, the decay rate should exhibit
+multiple steps due to thresholds for decays into a sequence of the
+two-dimensional magnon bands. For yet thicker films, such thresholds merge and
+crossover to the three-dimensional single-mode behavior: \Gamma |\Delta
+H|^{3/2}.",1208.0831v1
+2012-12-10,Heat-induced damping modification in YIG/Pt hetero-structures,"We experimentally demonstrate the manipulation of magnetization relaxation
+utilizing a temperature difference across the thickness of an yttrium iron
+garnet/platinum (YIG/Pt) hetero-structure: the damping is either increased or
+decreased depending on the sign of the temperature gradient. This effect might
+be explained by a thermally-induced spin torque on the magnetization
+precession. The heat-induced variation of the damping is detected by microwave
+techniques as well as by a DC voltage caused by spin pumping into the adjacent
+Pt layer and the subsequent conversion into a charge current by the inverse
+spin Hall effect.",1212.2073v1
+2013-02-25,Phase Diagram for Magnon Condensate in Yttrium Iron Garnet Film,"Recently, magnons, which are quasiparticles describing the collective motion
+of spins, were found to undergo Bose-Einstein condensation (BEC) at room
+temperature in films of Yttrium Iron Garnet (YIG). Unlike other quasiparticle
+BEC systems, this system has a spectrum with two degenerate minima, which makes
+it possible for the system to have two condensates in momentum space. Recent
+Brillouin Light scattering studies for a microwave-pumped YIG film of thickness
+d=5 $\mu$m and field H=1 kOe find a low-contrast interference pattern at the
+characteristic wavevector $Q$ of the magnon energy minimum. In this report, we
+show that this modulation pattern can be quantitatively explained as due to
+non-symmetric but coherent Bose-Einstein condensation of magnons into the two
+energy minima. Our theory predicts a transition from a high-contrast symmetric
+phase to a low-contrast non-symmetric phase on varying the $d$ and $H$, and a
+new type of collective oscillations.",1302.6128v1
+2013-02-27,Optimization of the yttrium iron garnet/platinum interface for spin pumping-based applications,"The dependence of the spin pumping efficiency and the spin mixing conductance
+on the surface processing of yttrium iron garnet (YIG) before the platinum (Pt)
+deposition has been investigated quantitatively. The ferromagnetic resonance
+driven spin pumping injects a spin polarized current into the Pt layer, which
+is transformed into an electromotive force by the inverse spin Hall effect. Our
+experiments show that the spin pumping effect indeed strongly depends on the
+YIG/Pt interface condition. We measure an enhancement of the inverse spin Hall
+voltage and the spin mixing conductance of more than two orders of magnitude
+with improved sample preparation.",1302.6697v1
+2013-08-15,Detection of the microwave spin pumping using the inverse spin Hall effect,"We report electrical detection of the dynamical part of the spin pumping
+current emitted during ferromagnetic resonance (FMR) using the inverse Spin
+Hall Effect (ISHE). The experiment is performed on a YIG$|$Pt bilayer. The
+choice of YIG, a magnetic insulator, ensures that no charge current flows
+between the two layers and only pure spin current produced by the magnetization
+dynamics are transferred into the adjacent strong spin-orbit Pt layer via spin
+pumping. To avoid measuring the parasitic eddy currents induced at the
+frequency of the microwave source, a resonance at half the frequency is induced
+using parametric excitation in the parallel geometry. Triggering this nonlinear
+effect allows to directly detect on a spectrum analyzer the microwave component
+of the ISHE voltage. Signals as large as 30 $\mu$V are measured for precession
+angles of a couple of degrees. This direct detection provides a novel efficient
+means to study magnetization dynamics on a very wide frequency range with great
+sensitivity.",1308.3433v2
+2013-10-17,Electrical Detection of Direct and Alternating Spin Current Injected from a Ferromagnetic Insulator into a Ferromagnetic Metal,"We report room temperature electrical detection of spin injection from a
+ferromagnetic insulator (YIG) into a ferromagnetic metal (Permalloy, Py).
+Non-equilibrium spins with both static and precessional spin polarizations are
+dynamically generated by the ferromagnetic resonance of YIG magnetization, and
+electrically detected by Py as dc and ac spin currents, respectively. The dc
+spin current is electrically detected via the inverse spin Hall effect of Py,
+while the ac spin current is converted to a dc voltage via the spin
+rectification effect of Py which is resonantly enhanced by dynamic exchange
+interaction between the ac spin current and the Py magnetization. Our results
+reveal a new path for developing insulator spintronics, which is distinct from
+the prevalent but controversial approach of using Pt as the spin current
+detector.",1310.4840v1
+2013-11-06,Investigation of Magnetic Proximity Effect inTa/YIG Bilayer Hall Bar Structure,"In this work, the investigation of magnetic proximity effect was extended to
+Ta which has been reported to have a negative spin Hall angle.
+Magnetoresistance and Hall measurements for in-plane and out-of-plane applied
+magnetic field sweeps were carried out at room temperature. The size of the MR
+ratio observed (~10-5) and its magnetization direction dependence are similar
+to that reported in Pt/YIG, both of which can be explained by the spin Hall
+magnetoresistance theory. Additionally, a flip of magnetoresistance polarity is
+observed at 4 K in the temperature dependent measurements, which can be
+explained by the magnetic proximity effect induced anisotropic
+magnetoresistance at low temperature. Our findings suggest that both magnetic
+proximity effect and spin Hall magnetoresistance have contribution to the
+recently observed unconventional magnetoresistance effect.",1311.1262v1
+2013-11-25,Spin-wave excitation and propagation in microstructured waveguides of yttrium iron garnet (YIG)/Pt bilayers,"We present an experimental study of spin-wave excitation and propagation in
+microstructured waveguides patterned from a 100 nm thick yttrium iron garnet
+(YIG)/platinum (Pt) bilayer. The life time of the spin waves is found to be
+more than an order of magnitude higher than in comparably sized metallic
+structures despite the fact that the Pt capping enhances the Gilbert damping.
+Utilizing microfocus Brillouin light scattering spectroscopy, we reveal the
+spin-wave mode structure for different excitation frequencies. An exponential
+spin-wave amplitude decay length of 31 {\mu}m is observed which is a
+significant step towards low damping, insulator based micro-magnonics.",1311.6305v1
+2014-05-08,Enhancement of Spin Pumping in $\mathrm{Y_3Fe_5O_{12}/Pt/Ni_{81}Fe_{19}}$ Trilayer Film,"We study spin pumping in a
+$\mathrm{Y_3Fe_5O_{12}(YIG)/Pt/Ni_{81}Fe_{19}(Py)}$ trilayer film by means of
+the inverse spin Hall effect (ISHE). When the ferromagnets are not excited
+simultaneously by a microwave, ISHE-induced voltage is of the opposite sign at
+each ferromagnetic resonance (FMR). The opposite sign is consistent with spin
+pumping of bilayer films. On the other hand, the voltage is of the same sign at
+each FMR when both the ferromagnets are excited simultaneously. Futhermore, the
+voltage greatly increases in magnitude. The observed voltage is unconventional;
+neither its sign nor magnitude can be expected from spin pumping of bilayer
+films. Control experiments show that the unconventional voltage is dominantly
+induced by spin pumping at the Py/Pt interface. Interaction between YIG and Py
+layers is a possible origin of the unconventional voltage.",1405.1929v1
+2014-09-19,Perpendicularly Biased YIG Tuners for the Fermilab Recycler 52.809 MHz Cavities,"For NOvA and future experiments requiring high intensity proton beams,
+Fermilab is in the process of upgrading the existing accelerator complex for
+increased proton production. One such improvement is to reduce the Main
+Injector cycle time, by performing slip stacking, previously done in the Main
+Injector, in the now repurposed Recycler Ring. Recycler slip stacking requires
+new tuneable RF cavities, discussed separately in these proceedings. These are
+quarter wave cavities resonant at 52.809 MHz with a 10 kHz tuning range. The 10
+kHz range is achieved by use of a tuner which has an electrical length of
+approximately one half wavelength at 52.809 MHz. The tuner is constructed from
+3 1/8 inch diameter rigid coaxial line, with 5 inches of its length containing
+perpendicularly biased, Al doped Yttrium Iron Garnet (YIG). The tuner design,
+measurements, and high power test results are presented.",1409.5762v1
+2014-11-25,Longitudinal spin Seebeck effect contribution in transverse spin Seebeck effect experiments in Pt/YIG and Pt/NFO,"We investigate the inverse spin Hall voltage of a 10nm thin Pt strip
+deposited on the magnetic insulators Y3Fe5O12 (YIG) and NiFe2O4 (NFO) with a
+temperature gradient in the film plane. We observe characteristics typical of
+the spin Seebeck effect, although we do not observe a change of sign of the
+voltage at the Pt strip when it is moved from hot to cold side, which is
+believed to be the most striking feature of the transverse spin Seebeck effect.
+Therefore, we relate the observed voltages to the longitudinal spin Seebeck
+effect generated by a parasitic out-of-plane temperature gradient, which can be
+simulated by contact tips of different material and heat conductivities and by
+tip heating. This work gives new insights into the interpretation of transverse
+spin Seebeck effect experiments, which are still under discussion.",1411.6790v1
+2014-12-11,Magnon Hall effect and anisotropic thermal transport in NiFe and YIG ferromagnets,"The Righi-Leduc effect refers to the thermal analogue of the Hall effect, for
+which the electric current is replaced by the heat current and the electric
+field by the temperature gradient. In both cases, the magnetic field generates
+a transverse force that deviates the carriers (electron, phonon, magnon) in the
+direction perpendicular to the current. In a ferromagnet, the magnetization
+plays the role of the magnetic field, and the corresponding effect is called
+anomalous Hall effect. Furthermore, a second transverse contribution due to the
+anisotropy, the planar Hall effect, is superimposed to the anomalous Hall
+effect. We report experimental evidence of the thermal counterpart of the Hall
+effects in ferromagnets, namely the magnon Hall effect (or equivalently the
+anomalous Righi-Leduc effect) and the planar Righi-Leduc effect, measured on
+ferromagnets that are either electrical conductor (NiFe) or insulator (YIG).
+The study shows the universal character of these new thermokinetic effects,
+related to the intrinsic chirality of the anisotropic ferromagnetic degrees of
+freedom.",1412.3723v1
+2015-02-24,High Quality Yttrium Iron Garnet Grown by Room Temperature Pulsed Laser Deposition and Subsequent Annealing,"We have investigated recrystallization of amorphous Yttrium Iron Garnet (YIG)
+by annealing in oxygen atmosphere. Our findings show that well below the
+melting temperature the material transforms into a fully epitaxial layer with
+exceptional quality, both structural and magnetic.\\ In ferromagnetic resonance
+(FMR) ultra low damping and extremely narrow linewidth can be observed. For a
+56 nm thick layer a damping constant of
+$\alpha$=(6.63$\pm$1.50)$\cdot$10$^{-5}$ is found and the linewidth at 9.6 GHz
+is as small as 1.30$\pm$0.05 Oe which are the lowest values for PLD grown thin
+films reported so far. Even for a 20 nm thick layer a damping constant of
+$\alpha$=(7.51$\pm$1.40)$\cdot$10$^{-5}$ is found which is the lowest value for
+ultrathin films published so far. The FMR linewidth in this case is
+3.49$\pm$0.10 Oe at 9.6 GHz. Our results not only present a method of
+depositing thin film YIG of unprecedented quality but also open up new options
+for the fabrication of thin film complex oxides or even other crystalline
+materials.",1502.06724v2
+2015-05-23,Long distance transport of magnon spin information in a magnetic insulator at room temperature,"The transport of spin information has been studied in various materials, such
+as metals, semiconductors and graphene. In these materials, spin is transported
+by diffusion of conduction electrons. Here we study the diffusion and
+relaxation of spin in a magnetic insulator, where the large bandgap prohibits
+the motion of electrons. Spin can still be transported, however, through the
+diffusion of non-equilibrium magnons, the quanta of spin wave excitations in
+magnetically ordered materials. Here we show experimentally that these magnons
+can be excited and detected fully electrically in linear response, and can
+transport spin angular momentum through the magnetic insulator yttrium iron
+garnet (YIG) over distances as large as 40 micrometer. We identify two
+transport regimes: the diffusion limited regime for distances shorter than the
+magnon relaxation length, and the relaxation limited regime for larger
+distances. With a model similar to the diffusion-relaxation model for electron
+spin transport in (semi)conducting materials, we extract the magnon relaxation
+length lambda = 9.4 micrometer in a 200 nm thin YIG film at room temperature.",1505.06325v1
+2015-05-28,Driving and detecting ferromagnetic resonance in insulators with the spin Hall effect,"We demonstrate the generation and detection of spin-torque ferromagnetic
+resonance in Pt/YIG bilayers. A unique attribute of this system is that the
+spin Hall effect lies at the heart of both the generation and detection
+processes and no charge current is passing through the insulating magnetic
+layer. When the YIG undergoes resonance, a dc voltage is detected
+longitudinally along the Pt that can be described by two components. One is the
+mixing of the spin Hall magnetoresistance with the microwave current. The other
+results from spin pumping into the Pt being converted to a dc current through
+the inverse spin Hall effect. The voltage is measured with applied magnetic
+field directions that range in-plane to nearly perpendicular. We find that for
+magnetic fields that are mostly out-of-plane, an imaginary component of the
+spin mixing conductance is required to model our data.",1505.07791v1
+2015-10-13,Optomagnonic whispering gallery microresonators,"Magnons in ferrimagnetic insulators such as yttrium iron garnet (YIG) have
+recently emerged as promising candidates for coherent information processing in
+microwave circuits. Here we demonstrate optical whispering gallery modes of a
+YIG sphere interrogated by a silicon nitride photonic waveguide, with quality
+factors approaching $10^6$ in the telecom c-band after surface treatments.
+Moreover, in contrast to conventional Faraday setup, this implementation allows
+input photon polarized colinearly to the magnetization to be scattered to a
+sideband mode of orthogonal polarization. This Brillouin scattering process is
+enhanced through triply resonant magnon, pump and signal photon modes - all of
+whispering gallery nature - within an ""optomagnonic cavity"". Our results show
+the potential use of magnons for mediating microwave-to-optical carrier
+conversion.",1510.03545v1
+2015-10-21,Magnetoresistance of heavy and light metal/ferromagnet bilayers,"We studied the magnetoresistance of normal metal (NM)/ferromagnet (FM)
+bilayers in the linear and nonlinear (current-dependent) regimes and compared
+it with the amplitude of the spin-orbit torques and thermally induced electric
+fields. Our experiments reveal that the magnetoresistance of the heavy NM/Co
+bilayers (NM = Ta, W, Pt) is phenomenologically similar to the spin Hall
+magnetoresistance (SMR) of YIG/Pt, but has a much larger anisotropy, of the
+order of 0.5%, which increases with the atomic number of the NM. This SMR-like
+behavior is absent in light NM/Co bilayers (NM = Ti, Cu), which present the
+standard AMR expected of polycrystalline FM layers. In the Ta, W, Pt/Co
+bilayers we find an additional magnetoresistance, directly proportional to the
+current and to the transverse component of the magnetization. This so-called
+unidirectional SMR, of the order of 0.005%, is largest in W and correlates with
+the amplitude of the antidamping spin-orbit torque. The unidirectional SMR is
+below the accuracy of our measurements in YIG/Pt.",1510.06285v1
+2015-12-14,Nonlocal Anomalous Hall Effect,"The anomalous Hall effect is deemed to be a unique transport property of
+ferromagnetic metals, caused by the concerted action of spin polarization and
+spin-orbit coupling. Nevertheless, recent experiments have shown that the
+effect also occurs in a nonmagnetic metal (Pt) in contact with a magnetic
+insulator (yttrium iron garnet (YIG)), even when precautions are taken to
+ensure there is no induced magnetization in the metal. We propose a theory of
+this effect based on the combined action of spin-dependent scattering from the
+magnetic interface and the spin Hall effect in the bulk of the metal. At
+variance with previous theories, we predict the effect to be of first order in
+the spin-orbit coupling, just as the conventional anomalous Hall effect -- the
+only difference being the spatial separation of the spin orbit interaction and
+the magnetization. For this reason we name this effect \textit{nonlocal
+anomalous Hall effect} and predict that its sign will be determined by the sign
+of the spin Hall angle in the metal. The AH conductivity that we calculate from
+our theory is in good agreement with the measured values in Pt/YIG structures.",1512.04146v1
+2016-01-03,Detection of DC currents and resistance measurements in longitudinal spin Seebeck effect experiments on Pt/YIG and Pt/NFO,"In this work we investigated thin films of the ferrimagnetic insulators YIG
+and NFO capped with thin Pt layers in terms of the longitudinal spin Seebeck
+effect (LSSE). The electric response detected in the Pt layer under an
+out-of-plane temperature gradient can be interpreted as a pure spin current
+converted into a charge current via the inverse spin Hall effect. Typically,
+the transverse voltage is the quantity investigated in LSSE measurements (in
+the range of \mu V). Here, we present the directly detected DC current (in the
+range of nA) as an alternative quantity. Furthermore, we investigate the
+resistance of the Pt layer in the LSSE configuration. We found an influence of
+the test current on the resistance. The typical shape of the LSSE curve varies
+for increasing test currents.",1601.00304v1
+2016-04-25,Magnon based logic in a multi-terminal YIG/Pt nanostructure,"Boolean logic is the foundation of modern digital information processing.
+Recently, there has been a growing interest in phenomena based on pure spin
+currents, which allow to move from charge to spin based logic gates. We study a
+proof-of-principle logic device based on the ferrimagnetic insulator Yttrium
+Iron Garnet (YIG), with Pt strips acting as injectors and detectors for
+nonequilibrium magnons. We experimentally observe incoherent superposition of
+magnons generated by different injectors. This allows to implement a fully
+functional majority gate, enabling multiple logic operations (AND and OR) in
+one and the same device. Clocking frequencies of the order of several GHz and
+straightforward down-scaling make our device promising for applications.",1604.07262v1
+2016-05-28,"Magnon Waves on Chains of YIG particles: Dispersion Relations, Faraday Rotation, and Power Transmission","We calculate the dispersion relations for magnon waves on a periodic chain of
+spherical or cylindrical Yttrium Iron Garnet (YIG) particles. We use the
+quasistatic approximation, appropriate when $kd \ll 1$, where $k$ is the wave
+number and $d$ the interparticle spacing. In this regime, because of the
+magnetic dipole-dipole interaction between the localized magnetic excitations
+on neighboring particles, dispersive magnon waves can propagate along the
+chain. The waves are analogous to plasmonic waves generated by electric
+dipole-dipole interactions between plasmons on neighboring metallic particles.
+The magnon waves can be longitudinal ($L$), transverse ($T$), or elliptically
+polarized. We find that a linearly polarized magnon wave undergoes a Faraday
+rotation as it propagates along the chain. The amount of Faraday rotation can
+be tuned by varying the off-diagonal component of the permeability tensor. We
+also discuss the possibility of wireless power transmission along the chain
+using these coupled magnon waves.",1605.08931v1
+2016-09-06,Chiral charge pumping in graphene deposited on a magnetic insulator,"We demonstrate that a sizable chiral charge pumping can be achieved at room
+temperature in graphene/Yttrium Iron Garnet (YIG) bilayer systems. The effect,
+which cannot be attributed to the ordinary spin pumping, reveals itself in the
+creation of a dc electric field/voltage in graphene as a response to the
+dynamic magnetic excitations (spin waves) in an adjacent out-of-plane
+magnetized YIG film. We show that the induced voltage changes its sign when the
+orientation of the static magnetization is reversed, clearly indicating the
+broken spatial inversion symmetry in the studied system. The strength of effect
+shows a non-monotonous dependence on the spin-wave frequency, in agreement with
+the proposed theoretical model.",1609.01613v2
+2016-10-18,Spin transport in antiferromagnetic NiO and magnetoresistance in Y$_3$Fe$_5$O$_{12}$/NiO/Pt structures,"We have studied spin transport and magnetoresistance in yttrium iron garnet
+(YIG)/NiO/Pt trilayers with varied NiO thickness. To characterize the spin
+transport through NiO we excite ferromagnetic resonance in YIG with a microwave
+frequency magnetic field and detect the voltage associated with the inverse
+spin-Hall effect (ISHE) in the Pt layer. The ISHE signal is found to decay
+exponentially with the NiO thickness with a characteristic decay length of 3.9
+nm. This is contrasted with the magnetoresistance in these same structures. The
+symmetry of the magnetoresistive response is consistent with spin-Hall
+magnetoresistance (SMR). However, in contrast to the ISHE response, as the NiO
+thickness increases the SMR signal goes towards zero abruptly at a NiO
+thickness of $\simeq$ 4 nm, highlighting the different length scales associated
+with the spin-transport in NiO and SMR in such trilayers.",1610.05760v1
+2016-10-26,Time-resolved measurements of surface spin-wave pulses at millikelvin temperatures,"In this work, we experimentally investigate the propagation of pulsed
+magnetostatic surface spin-wave (magnon) signals in an yttrium iron garnet
+(YIG) waveguide at millikelvin temperatures. Our measurements are performed in
+a dilution refrigerator at microwave frequencies. The excellent signal-to-noise
+ratio afforded by the low-temperature environment allows the propagation of the
+pulses to be observed in detail. The work gives insight both into
+low-temperature magnon dynamics in YIG and the potential application of systems
+of propagating magnons to solid-state quantum information processing.",1610.08402v2
+2016-10-29,Tailoring magnetic insulator proximity effects in graphene: First-principles calculations,"We report a systematic first-principles investigation of the influence of
+different magnetic insulators on the magnetic proximity effect induced in
+graphene. Four different magnetic insulators are considered: two ferromagnetic
+europium chalcogenides namely EuO and EuS and two ferrimagnetic insulators
+yttrium iron garnet (YIG) and cobalt ferrite (CFO). The obtained
+exchange-splitting varies from tens to hundreds of meV. We also find an
+electron doping induced by YIG and europium chalcogenides substrates, that
+shift the Fermi level up to 0.78 eV and 1.3 eV respectively, whereas hole
+doping up to 0.5 eV is generated by CFO. Furthermore, we study the variation of
+the extracted exchange and tight binding parameters as a function of the EuO
+and EuS thicknesses. We show that those parameters are robust to thickness
+variation such that a single monolayer of magnetic insulator can induce a large
+magnetic proximity effect on graphene. Those findings pave the way towards
+possible engineering of graphene spin-gating by proximity effect especially in
+view of recent experiments advancement.",1610.09554v1
+2016-11-18,Temporal evolution of auto-oscillations in a YIG/Pt microdisc driven by pulsed spin Hall effect-induced spin-transfer torque,"The temporal evolution of pulsed Spin Hall Effect - Spin Transfer Torque
+(SHE-STT) driven auto-oscillations in a Yttrium Iron Garnet (YIG) / platinum
+(Pt) microdisc is studied experimentally using time-resolved Brillouin Light
+Scattering (BLS) spectroscopy. It is demonstrated that the frequency of the
+auto-oscillations is different in the center and at the edge of the
+investigated disc that is related to the simultaneous STT excitation of a
+bullet and a non-localized spin-wave mode. Furthermore, the magnetization
+precession intensity is found to saturate on a time scale of 20 ns or longer,
+depending on the current density. For this reason, our findings suggest that a
+proper ratio between the current and the pulse duration is of crucial
+importance for future STT-based devices.",1611.06054v1
+2016-12-21,Pure spin current transport in gallium doped zinc oxide,"We study the flow of a pure spin current through zinc oxide by measuring the
+spin Hall magnetoresistance (SMR) in thin film trilayer samples consisting of
+bismuth-substituted yttrium iron garnet (Bi:YIG), gallium-doped zinc oxide
+(Ga:ZnO), and platinum. We investigate the dependence of the SMR magnitude on
+the thickness of the Ga:ZnO interlayer and compare to a Bi:YIG/Pt bilayer. We
+find that the SMR magnitude is reduced by almost one order of magnitude upon
+inserting a Ga:ZnO interlayer, and continuously decreases with increasing
+interlayer thickness. Nevertheless, the SMR stays finite even for a
+$12\;\mathrm{nm}$ thick Ga:ZnO interlayer. These results show that a pure spin
+current indeed can propagate through a several nm-thick degenerately doped zinc
+oxide layer. We also observe differences in both the temperature and the field
+dependence of the SMR when comparing tri- and bilayers. Finally, we compare our
+data to predictions of a model based on spin diffusion. This shows that
+interface resistances play a crucial role for the SMR magnitude in these
+trilayer structures.",1612.07239v1
+2017-01-31,Lateral transport properties of thermally excited magnons in yttrium iron garnet films,"Spin information carried by magnons is attractive for computing technology
+and the development of magnon-based computing circuits is of great interest.
+However, magnon transport in insulators has been challenging, different from
+the clear physical picture for spin transport in conductors. Here we
+investigate the lateral transport properties of thermally excited magnons in
+yttrium iron garnet (YIG), a model magnetic insulator. Polarity reversals of
+detected spins in non-local geometry devices have been experimentally observed
+and are strongly dependent on temperature, YIG film thickness, and
+injector-detector separation distance. A competing two-channel transport model
+for thermally excited magnons is proposed, which is qualitatively consistent
+with the spin signal behavior. In addition to the fundamental significance for
+thermal magnon transport, our work furthers the development of magnonics by
+creating an easily accessible magnon source with controllable transport",1701.08932v1
+2017-02-03,Quantitative investigation of the inverse Rashba-Edelstein effect in Bi/Ag and Ag/Bi on YIG,"The inverse Rashba-Edelstein effect (IREE) is a spin conversion mechanism
+that recently attracts attention in spintronics and condensed matter physics.
+In this letter, we report an investigation of the IREE in Bi/Ag by using
+ferrimagnetic insulator yttrium iron garnet (YIG). We prepared two types of
+samples with opposite directions of the Rashba field by changing a stacking
+order of Bi and Ag. An electric current generated by the IREE was observed from
+both stacks, and an efficiency of spin conversion -characterized by the IREE
+length- was estimated by taking into account a number of contributions left out
+in previous studies. This study provides a further insight into the IREE spin
+conversion mechanism: important step towards achieving efficient spin-charge
+conversion devices.",1702.00890v1
+2017-04-28,Thermal Control of the Magnon-Photon Coupling in a Notch Filter coupled to a Yttrium-Iron-Garnet/Platinum System,"We report thermal control of mode hybridization between the ferromagnetic
+resonance (FMR) and a planar resonator (notch filter) working at 4.74 GHz. The
+chosen magnetic material is a ferrimagnetic insulator (Yttrium Iron Garnet:
+YIG) covered by 6 nm of platinum (Pt). A current induced heating method has
+been used in order to enhance the temperature of the YIG/Pt system. The device
+permits us to control the transmission spectra and the magnon-photon coupling
+strength at room temperature. These experimental findings reveal potentially
+applicable tunable microwave filtering function.",1704.08896v3
+2017-05-02,Magnetic Field-Free Giant Magnetoresistance in a Proximity- and Gate-Induced Graphene Spin Valve,"Due to its two dimensional nature, ferromagnetism and charge doping can be
+induced by proximity and electric field effects in graphene. Taking advantage
+of these features, we propose an electrically engineered spin valve by
+combining two magnetic insulators (using EuO, EuS, or YIG) and three coating
+gates. Two top gates are used to cancel the heavy electron doping's in these
+magnets and one back gate is used to utilize the normal or half-metallic
+ferromagnetisms. We demonstrate that, when the second top gate is tuned to
+utilize the insulating or spin insulating states, huge giant magnetoresistance
+(GMR) at high temperature (several times of $10^5\%$ at 68K and 100K) can be
+achieved for EuO and YIG. These results imply a distinguished GMR that is
+magnetism tunable, vertical configured (ferromagnetism versus insulating), and
+magnetic field-free. Our work may offer a viable path to a tantalizing magnetic
+field-free spintronics.",1705.00773v1
+2017-05-18,The Final Chapter In The Saga Of YIG,"The magnetic insulator Yttrium Iron Garnet can be grown with exceptional
+quality, has a ferrimagnetic transition temperature of nearly 600 K, and is
+used in microwave and spintronic devices that can operate at room temperature.
+The most accurate prior measurements of the magnon spectrum date back nearly 40
+years, but cover only 3 of the lowest energy modes out of 20 distinct magnon
+branches. Here we have used time-of-flight inelastic neutron scattering to
+measure the full magnon spectrum throughout the Brillouin zone. We find that
+the existing model of the excitation spectrum, well known from an earlier work
+titled ""The Saga of YIG"", fails to describe the optical magnon modes. Using a
+very general spin Hamiltonian, we show that the magnetic interactions are both
+longer-ranged and more complex than was previously understood. The results
+provide the basis for accurate microscopic models of the finite temperature
+magnetic properties of Yttrium Iron Garnet, necessary for next-generation
+electronic devices.",1705.06594v1
+2017-07-20,Bistability of Cavity Magnon Polaritons,"We report the first observation of the magnon-polariton bistability in a
+cavity magnonics system consisting of cavity photons strongly interacting with
+the magnons in a small yttrium iron garnet (YIG) sphere. The bistable behaviors
+are emerged as sharp frequency switchings of the cavity magnon-polaritons
+(CMPs) and related to the transition between states with large and small number
+of polaritons. In our experiment, we align, respectively, the [100] and [110]
+crystallographic axes of the YIG sphere parallel to the static magnetic field
+and find very different bistable behaviors (e.g., clockwise and
+counter-clockwise hysteresis loops) in these two cases. The experimental
+results are well fitted and explained as being due to the Kerr nonlinearity
+with either positive or negative coefficient. Moreover, when the magnetic field
+is tuned away from the anticrossing point of CMPs, we observe simultaneous
+bistability of both magnons and cavity photons by applying a drive field on the
+lower branch.",1707.06509v2
+2018-03-09,Spin transport across antiferromagnets induced by the spin Seebeck effect,"For prospective spintronics devices based on the propagation of pure spin
+currents, antiferromagnets are an interesting class of materials that
+potentially entail a number of advantages as compared to ferromagnets. Here, we
+present a detailed theoretical study of magnonic spin current transport in
+ferromagnetic-antiferromagnetic multilayers by using atomistic spin dynamics
+simulations. The relevant length scales of magnonic spin transport in
+antiferromagnets are determined. We demonstrate the transfer of angular
+momentum from a ferromagnet into an antiferromagnet due to the excitation of
+only one magnon branch in the antiferromagnet. As an experimental system, we
+ascertain the transport across an antiferromagnet in
+YIG$|$Ir$_{20}$Mn$_{80}|$Pt heterostructures. We determine the spin transport
+signals for spin currents generated in the YIG by the spin Seebeck effect and
+compare to measurements of the spin Hall magnetoresistance in the
+heterostructure stack. By means of temperature-dependent and
+thickness-dependent measurements, we deduce conclusions on the spin transport
+mechanism across IrMn and furthermore correlate it to its
+paramagnetic-antiferromagnetic phase transition.",1803.03416v1
+2018-03-15,Synthetic antiferromagnetic coupling between ultra-thin insulating garnets,"The use of magnetic insulators is attracting a lot of interest due to a rich
+variety of spin-dependent phenomena with potential applications to spintronic
+devices. Here we report ultra-thin yttrium iron garnet (YIG) / gadolinium iron
+garnet (GdIG) insulating bilayers on gadolinium iron garnet (GGG). From spin
+Hall magnetoresistance (SMR) and X-ray magnetic circular dichroism
+measurements, we show that the YIG and GdIG magnetically couple antiparallel
+even in moderate in-plane magnetic fields. The results demonstrate an
+all-insulating equivalent of a synthetic antiferromagnet in a garnet-based thin
+film heterostructure and could open new venues for insulators in magnetic
+devices. As an example, we demonstrate a memory element with orthogonal
+magnetization switching that can be read by SMR.",1803.05545v1
+2018-04-12,Spin colossal magnetoresistance in an antiferromagnetic insulator,"Colossal magnetoresistance (CMR) refers to a large change in electrical
+conductivity induced by a magnetic field in the vicinity of a metal-insulator
+transition and has inspired extensive studies for decades\cite{Ramirez1997,
+Tokura2006}. Here we demonstrate an analogous spin effect near the N\'eel
+temperature $T_{\rm{N}}$=296 K of the antiferromagnetic insulator \CrO. Using a
+yttrium iron garnet \YIG/\CrO/Pt trilayer, we injected a spin current from the
+YIG into the \CrO layer, and collected via the inverse spin Hall effect the
+signal transmitted in the heavy metal Pt. We observed a change by two orders of
+magnitude in the transmitted spin current within 14 K of the N\'eel
+temperature. This transition between spin conducting and nonconducting states
+could be also modulated by a magnetic field in isothermal conditions. This
+effect, that we term spin colossal magnetoresistance (SCMR), has the potential
+to simplify the design of fundamental spintronics components, for instance
+enabling the realization of spin current switches or spin-current based
+memories.",1804.04516v1
+2018-05-29,Efficient injection and detection of out-of-plane spins via the anomalous spin Hall effect in permalloy nanowires,"We report a novel mechanism for the electrical injection and detection of
+out-of-plane spin accumulation via the anomalous spin Hall effect (ASHE), where
+the direction of the spin accumulation can be controlled by manipulating the
+magnetization of the ferromagnet. This mechanism is distinct from the spin Hall
+effect (SHE), where the spin accumulation is created along a fixed direction
+parallel to an interface. We demonstrate this unique property of the ASHE in
+nanowires made of permalloy (Py), to inject and detect out-of-plane spin
+accumulation in a magnetic insulator, yttrium iron garnet (YIG). We show that
+the efficiency for the injection/detection of out-of-plane spins can be up to
+50% of that of in-plane spins. We further report the possibility to detect spin
+currents parallel to the Py/YIG interface for spins fully oriented in the
+out-of-plane direction, resulting in a sign reversal of the non-local magnon
+spin signal. The new mechanisms that we have demonstrated are highly relevant
+for spin torque devices and applications.",1805.11575v1
+2018-06-12,Resonant spin wave excitation in magnetoplasmonic bilayers by short laser pulses,"In magnetically ordered solids a static magnetic field can be generated by
+virtue of the transverse magneto-optical Kerr effect (TMOKE). Moreover, the
+latter was shown to be dramatically enhanced due to the optical excitation of
+surface plasmons in nanostructures with relatively small optical losses. In
+this paper we suggest a new method of resonant optical excitations in a
+prototypical bilayer composed of noble metal (Au) with grating and a
+ferromagnet thin film of yttrium iron garnet (YIG) via frequency comb. Based on
+magnetization dynamics simulations we show that for the frequency comb with the
+parameters, chosen in resonant with spin-wave excitations of YIG, TMOKE is
+drastically enhanced, hinting towards possible technological applications in
+the optical control of spintronics systems.",1806.04764v1
+2018-07-02,Picosecond acoustic excitation driven ultrafast magnetization dynamics in dielectric Bi-substituted yttrium iron garnet,"Using femtosecond optical pulses, we have investigated the ultrafast
+magnetization dynamics induced in a dielectric film of bismuth-substituted
+yttrium iron garnet (Bi-YIG) buried below a thick Cu/Pt metallic bilayer. We
+show that exciting the sample from Pt surface launches an acoustic strain pulse
+propagating into the garnet film. We discovered that this strain pulse induces
+a coherent magnetization precession in the Bi-YIG at the frequency of the
+ferromagnetic resonance. The observed phenomena can be explain by
+strain-induced changes of magnetocristalline anisotropy via the inverse
+magnetostriction effect. These findings open new perspectives toward the
+control of the magnetization in magnetic garnets embedded in complex
+heterostructure devices.",1807.00610v1
+2018-09-30,Magnon Valves Based on YIG/NiO/YIG All-Insulating Magnon Junctions,"As an alternative angular momentum carrier, magnons or spin waves can be
+utilized to encode information and breed magnon-based circuits with ultralow
+power consumption and non-Boolean data processing capability. In order to
+construct such a circuit, it is indispensable to design some electronic
+components with both long magnon decay and coherence length and effective
+control over magnon transport. Here we show that an all-insulating magnon
+junctions composed by a magnetic insulator (MI1)/antiferromagnetic insulator
+(AFI)/magnetic insulator (MI2) sandwich (Y3Fe5O12/NiO/Y3Fe5O12) can completely
+turn a thermogradient-induced magnon current on or off as the two Y3Fe5O12
+layers are aligned parallel or anti-parallel. The magnon decay length in NiO is
+about 3.5~4.5 nm between 100 K and 200 K for thermally activated magnons. The
+insulating magnon valve (magnon junction), as a basic building block, possibly
+shed light on the naissance of efficient magnon-based circuits, including
+non-Boolean logic, memory, diode, transistors, magnon waveguide and switches
+with sizable on-off ratios.",1810.00380v1
+2018-10-17,Conventional magnon BEC in YIG film,"The conventional magnon Bose-Einstein condensation (BEC of magnons with k =
+0) is a coherent state of excited magnons described by a common wave function.
+It was observed first in antiferromagnetic superfluid states of 3He. Here we
+report on the discovery of a very similar magnon BEC in ferrimagnetic film at
+room temperature. The experiments were performed in Yttrium Iron Garnet (YIG)
+films at a magnetic field oriented perpendicular to the film. The high-density
+quasiequilibrium state of excited magnon was formed by methods of pulse and/or
+Continuous Waves (CW) magnetic resonance. We have observed a Long Lived
+Induction Decay Signals (LLIDS), well known as a signature of spin
+superfluidity. We demonstrate that the BEC state may maintain permanently by
+continuous replenishment of magnons with a small radiofrequency (RF) field. Our
+finding opens the way for development of potential supermagnonic applications
+at an ambient conditions.",1810.08051v2
+2018-11-14,Tunable space-time crystal in room-temperature magnetodielectrics,"We report the experimental realization of a space-time crystal with tunable
+periodicity in time and space in the magnon Bose-Einstein Condensate (BEC),
+formed in a room-temperature Yttrium Iron Garnet (YIG) film by radio-frequency
+space-homogeneous magnetic field. The magnon BEC is prepared to have a well
+defined frequency and non-zero wavevector. We demonstrate how the crystalline
+""density"" as well as the time and space textures of the resulting crystal may
+be tuned by varying the experimental parameters: external static magnetic
+field, temperature, thickness of the YIG film and power of the radio-frequency
+field. The proposed space-time crystals provide a new dimension for exploring
+dynamical phases of matter and can serve as a model nonlinear Floquet system,
+that brings in touch the rich fields of classical nonlinear waves, magnonics
+and periodically driven systems.",1811.05801v1
+2019-03-01,Nanoscale X-Ray Imaging of Spin Dynamics in Yttrium Iron Garnet,"Time-resolved scanning transmission x-ray microscopy (TR-STXM) has been used
+for the direct imaging of spin wave dynamics in thin film yttrium iron garnet
+(YIG) with spatial resolution in the sub 100 nm range. Application of this
+x-ray transmission technique to single crystalline garnet films was achieved by
+extracting a lamella (13x5x0.185 $\mathrm{\mu m^3}$) of liquid phase epitaxy
+grown YIG thin film out of a gadolinium gallium garnet substrate. Spin waves in
+the sample were measured along the Damon-Eshbach and backward volume directions
+of propagation at gigahertz frequencies and with wavelengths in a range between
+100~nm and 10~$\mathrm{\mu}$m. The results were compared to theoretical models.
+Here, the widely used approximate dispersion equation for dipole-exchange spin
+waves proved to be insufficient for describing the observed Damon-Eshbach type
+modes. For achieving an accurate description, we made use of the full
+analytical theory taking mode-hybridization effects into account.",1903.00498v1
+2019-03-05,Optimal mode matching in cavity optomagnonics,"Inelastic scattering of photons is a promising technique to manipulate
+magnons but it suffers from weak intrinsic coupling. We theoretically discuss
+an idea to increase optomagnonic coupling in optical whispering gallery mode
+cavities, by generalizing previous analysis to include the exchange
+interaction. We predict that the optomagnonic coupling constant to surface
+magnons in yttrium iron garnet (YIG) spheres with radius $300\,\mathrm{\mu}$m
+can be up to $40$ times larger than that to the macrospin Kittel mode. Whereas
+this enhancement falls short of the requirements for magnon manipulation in
+YIG, nanostructuring and/or materials with larger magneto-optical constants can
+bridge this gap.",1903.01718v2
+2019-03-09,Theory of the magnon Kerr effect in cavity magnonics,"We develop a theory for the magnon Kerr effect in a cavity magnonics system,
+consisting of magnons in a small yttrium iron garnet (YIG) sphere strongly
+coupled to cavity photons, and use it to study the bistability in this hybrid
+system. To have a complete picture of the bistability phenomenon, we analyze
+two different cases in driving the cavity magnonics system, i.e., directly
+pumping the YIG sphere and the cavity, respectively. In both cases, the magnon
+frequency shifts due to the Kerr effect exhibit a similar bistable behavior but
+the corresponding critical powers are different. Moreover, we show how the
+bistability of the system can be demonstrated using the transmission spectrum
+of the cavity. Our results are valid in a wide parameter regime and generalize
+the theory of bistability in a cavity magnonics system.",1903.03754v1
+2019-03-14,Electrical control of spin mixing conductance in a Y$_3$Fe$_5$O$_{12}$/Platinum bilayer,"We report a tunable spin mixing conductance, up to $\pm 22\%$, in a
+Y${}_{3}$Fe${}_{5}$O${}_{12}$/Platinum (YIG/Pt) bilayer.This control is
+achieved by applying a gate voltage with an ionic gate technique, which
+exhibits a gate-dependent ferromagnetic resonance line width. Furthermore, we
+observed a gate-dependent spin pumping and spin Hall angle in the Pt layer,
+which is also tunable up to $\pm$ 13.6\%. This work experimentally demonstrates
+spin current control through spin pumping and a gate voltage in a YIG/Pt
+bilayer, demonstrating the crucial role of the interfacial charge density for
+the spin transport properties in magnetic insulator/heavy metal bilayers.",1903.05865v1
+2019-03-29,Quantum Simulation of the Fermion-Boson Composite Quasi-Particles with a Driven Qubit-Magnon Hybrid Quantum System,"We experimentally demonstrate strong coupling between the ferromagnetic
+magnons in a small yttrium-iron-garnet (YIG) sphere and the drive-field-induced
+dressed states of a superconducting qubit, which gives rise to the double
+dressing of the superconducting qubit. The YIG sphere and the superconducting
+qubit are embedded in a microwave cavity and the effective coupling between
+them is mediated by the virtual cavity photons. The theoretical results fit the
+experimental observations well in a wide region of the drive-field power
+resonantly applied to the superconducting qubit and reveal that the driven
+qubit-magnon hybrid quantum system can be harnessed to emulate a
+particle-hole-symmetric pair coupled to a bosonic mode. This hybrid quantum
+system offers a novel platform for quantum simulation of the composite
+quasi-particles consisting of fermions and bosons.",1903.12498v1
+2019-05-04,Identification and time-resolved study of YIG spin wave modes in a MW cavity in strong coupling regime,"Recently, the hybridization of microwave-frequency cavity modes with
+collective spin excitations attracted large interest for the implementation of
+quantum computation protocols, which exploit the transfer of information among
+these two physical systems. Here, we investigate the interaction among the
+magnetization precession modes of a small YIG sphere and the MW electromagnetic
+modes, resonating in a tridimensional aluminum cavity. In the strong coupling
+regime, anti-crossing features were observed in correspondence of various
+magnetostatic modes, which were excited in a magnetically saturated sample.
+Time-resolved studies show evidence of Rabi oscillations, demonstrating
+coherent exchange of energy among photons and magnons modes. To facilitate the
+analysis of the standing spin-wave patterns, we propose here a new procedure,
+based on the introduction of a novel functional variable. The resulting easier
+identification of magnetostatic modes can be exploited to investigate, control
+and compare many-levels hybrid systems in cavity- and opto-magnonics research.",1905.01522v2
+2019-06-11,Proximity magnetoresistance in graphene induced by magnetic insulators,"We demonstrate the existence of Giant proximity magnetoresistance (PMR)
+effect in a graphene spin valve where spin polarization is induced by a nearby
+magnetic insulator. PMR calculations were performed for yttrium iron garnet
+(YIG), cobalt ferrite (CFO), and two europium chalcogenides EuO and EuS. We
+find a significant PMR (up to 100%) values defined as a relative change of
+graphene conductance with respect to parallel and antiparallel alignment of two
+proximity induced magnetic regions within graphene. Namely, for high Curie
+temperature (Tc) CFO and YIG insulators which are particularly important for
+applications, we obtain 22% and 77% at room temperature, respectively. For low
+Tc chalcogenides, EuO and EuS, the PMR is 100% in both cases. Furthermore, the
+PMR is robust with respect to system dimensions and edge type termination. Our
+findings show that it is possible to induce spin polarized currents in graphene
+with no direct injection through magnetic materials.",1906.04469v1
+2019-06-30,Large spatial Schrodinger cat using a levitated ferrimagnetic nanoparticle,"The superposition principle is one of the main tenets of quantum mechanics.
+Despite its counter-intuitiveness, it has been experimentally verified using
+electrons, photons, atoms, and molecules. However, a similar experimental
+demonstration using a nano or a micro particle is non-existent. Here in this
+Letter, exploiting macroscopic quantum coherence and quantum tunneling, we
+propose an experiment using levitated magnetic nanoparticle to demonstrate such
+an effect. It is shown that the spatial separation between the delocalized
+wavepackets of a $20~$nm ferrimagnetic yttrium iron garnet (YIG) nanoparticle
+can be as large as $5~$$\mu$m. We argue that this large spatial separation can
+be used to test different modifications such as collapse models to the standard
+quantum mechanics. Furthermore, we show that the spatial superposition of a
+core-shell structure, a YIG core and a non-magnetic silica shell, can be used
+to probe quantum gravity.",1907.00415v4
+2019-10-09,Magnetic field dependence of the nonlocal spin Seebeck effect in Pt/YIG/Pt systems at low temperatures,"We report the nonlocal spin Seebeck effect (nlSSE) in a lateral configuration
+of Pt/Y$_3$Fe$_5$O$_{12}$(YIG)/Pt systems as a function of the magnetic field
+$B$ (up to 10 T) at various temperatures $T$ (3 K < $T$ < 300 K). The nlSSE
+voltage decreases with increasing $B$ in a linear regime with respect to the
+input power (the applied charge-current squared $I^2$). The reduction of the
+nlSSE becomes substantial when the Zeeman energy exceeds thermal energy at low
+temperatures, which can be interpreted as freeze-out of magnons relevant for
+the nlSSE. Furthermore, we found the non-linear power dependence of the nlSSE
+with increasing $I$ at low temperatures ($T$ < 20 K), at which the $B$-induced
+signal reduction becomes less visible. Our experimental results suggest that in
+the non-linear regime high-energy magnons are over populated than those
+expected from the thermal energy. We also estimate the magnon spin diffusion
+length as functions of $B$ and $T$.",1910.04046v1
+2019-10-31,Coherent spin pumping in a strongly coupled magnon-magnon hybrid system,"We experimentally identify coherent spin pumping in the magnon-magnon hybrid
+modes of permalloy/yttrium iron garnet (Py/YIG) bilayers. Using broadband
+ferromagnetic resonance, an ""avoided crossing"" is observed between the uniform
+mode of Py and the spin wave mode of YIG due to the fieldlike interfacial
+exchange coupling. We also identify additional linewidth suppression and
+enhancement for the in-phase and out-of-phase hybrid modes, respectively,
+\textcolor{black}{which can be interpreted as concerted dampinglike torque from
+spin pumping}. Our analysis predicts inverse proportionality of both fieldlike
+and dampinglike torques to the square root of the Py thickness, which
+quantitatively agrees with experiments.",1910.14470v2
+2019-12-29,Synchronized excitation of magnetization dynamics via spin waves in Bi-YIG thin film by slot line waveguide,"We have studied magnetization dynamics of a single Bi-YIG thin film by means
+of the high frequency power response induced by a slot line waveguide. Multiple
+absorption peaks that correspond to excitement states in magnetization dynamics
+appeared without the ferromagnetic resonance (FMR) condition. The peaks were
+strongly influenced by a waveguide line width and a distance between the lines.
+Micromagnetics simulation reveals that each line induces a local magnetization
+dynamics oscillation and generates spin waves. The spin wave that propagates
+from one of the lines interferences with the other side of local magnetization
+dynamics oscillation around the other line, resulting in an amplification of
+the oscillation when they are in synchronization with each other. This
+amplification occurs at both sides of the lines by the interference. Thus, the
+possible mechanism of the excitation in the magnetization dynamics oscillation
+is the synchronization of mutual magnetization dynamics oscillation via spin
+waves. This technique resonantly excites the local magnetization dynamics
+without the FMR condition, which is applicable as a highly coherent spin waves
+source.",1912.12663v1
+2019-12-30,Hybrid nanophotonic-nanomagnonic SiC-YiG quantum sensor: II/ optical fiber based ODMR and OP-PELDOR experiments on bulk HPSI 4H-SiC,"Here I present my first fiber based coupled optical and EPR experiments
+associated to the development of a new SiC-YiG quantum sensor that I recently
+theoretically described (arXiv:1912.11634). This quantum sensor was designed to
+allow sub-nanoscale single external spin sensitivity optically detected pulsed
+electron electron double resonance spectroscopy, using an X band pulsed EPR
+spectrometer, an optical fiber, and a photoluminescence setup. First key
+experiments before the demonstration of ODPELDOR spectroscopy are presented
+here. They were performed on a bulk 4H-SiC sample containing an ensemble of
+residual V2 color centers (spin S=3/2). Here I demonstrate i/ optical pumping
+assisted pulsed EPR experiments, ii/ fiber based ODMR and optically detected
+RABI oscillations, and iii/ optical pumping assisted PELDOR experiments, and
+iv/ some spin wave resonance experiments. Those experiments confirm the
+feasability of the new quantum sensing approach proposed.",1912.13111v1
+2020-05-10,Stationary entanglement between light and microwave via ferromagnetic magnons,"We show how to generate stationary entanglement between light and microwave
+in a hybrid opto-electro-magnonical system which mainly consists of a microwave
+cavity, a yttrium iron garnet (YIG) sphere and a nanofiber. The optical modes
+in nanofiber can evanescently coupled to whispering gallery modes, that are
+able to interact with magnon mode via spin-orbit interaction, in YIG sphere,
+while the microwave cavity photons and magnons are coupled through magnetic
+dipole interaction simultaneously. Under reasonable parameter regimes, pretty
+amount of entanglement can be generated, and it also shows persistence against
+temperature. Our work is expected to provide a new perspective for building
+more advanced and comprehensive quantum networks along with magnons for
+fast-developing quantum technology and for studying the macroscopic quantum
+phenomena.",2005.04581v3
+2020-06-17,Magnon Polarons induced by a magnetic field gradient,"In this work, we report the theoretical possibility of generating magnon
+polaron excitations through a space-varying magnetic field. The spatial
+dependence of the magnetic field in the Zeeman interaction gives rise to a
+magnon-phonon coupling when a magnetic field gradient is applied, and such a
+coupling depends directly on the strength of the gradient. It is also predicted
+that the direction of the magnetic field gradient allows control over which
+phonon polarization couples to the magnons in the material. Here we develop the
+calculations of the magnon-phonon coupling for an arbitrary (anti)ferromagnet,
+which are later used to numerically study its consequences. These results are
+compared to the ones obtained with the phenomenological magnetoelastic coupling
+in YIG, where we show that the magnon polaron bandgap seen in YIG can be also
+obtained with a magnetic field gradient of $\sim 0.1$T/m which can be achieved
+with the current experimental techniques. Our results propose a new way of
+controlling the magnetoelastic coupling in an arbitrary material and open a new
+route to exploit the magnon-phonon interaction in magnonic and spintronic
+devices.",2006.09839v1
+2020-09-09,Effect of dipolar interactions on cavity magnon-polaritons,"The strong photon-magnon coupling between an electromagnetic cavity and two
+yttrium iron garnet (YIG) spheres has been investigated in the context of a
+strong mutual dipolar interaction between the spheres. A decrease in the
+coupling strength between the YIG spheres and the electromagnetic cavity is
+observed, along with an increase of the total magnetic losses, as the distance
+between the spheres is decreased. A model of inhomogeneous broadening of the
+ferromagnetic resonance linewidth, partly mitigated by the dipolar narrowing
+effect, reproduces the reduction in the coupling strength observed
+experimentally. These findings have important implications for the
+understanding of strongly coupled photon-magnon system involving densely packed
+magnetic objects, such as ferromagnetic nanowires arrays, in which the total
+coupling strength with an electromagnetic cavity might become limited due to
+mutual dipolar interactions.",2009.04557v1
+2020-10-09,Einstein-Podolsky-Rosen entanglement and asymmetric steering between distant macroscopic mechanical and magnonic systems,"We propose a deterministic scheme for establishing hybrid
+Einstein-Podolsky-Rosen (EPR) entanglement channel between a macroscopic
+mechanical oscillator and a magnon mode in a distant yttrium-iron-garnet (YIG)
+sphere across about ten gigahertz of frequency difference. The system consists
+of a driven electromechanical cavity which is unidirectionally coupled to a
+distant electromagnonical cavity inside which a YIG sphere is placed. We find
+that far beyond the sideband-resolved regime in the electromechanical
+subsystem, stationary phonon-magnon EPR entanglement can be achieved. This is
+realized by utilizing the output field of the electromechanical cavity being an
+intermediary which distributes the electromechanical entanglement to the
+magnons, thus establishing a remote phonon-magnon entanglement. The EPR
+entanglement is strong enough such that phonon-magnon quantum steering can be
+attainable in an asymmetric manner. This long-distance macroscopic hybrid EPR
+entanglement and steering enable potential applications not only in fundamental
+tests of quantum mechanics at the macro scale, but also in quantum networking
+and one-sided device-independent quantum cryptography based on magnonics and
+electromechanics.",2010.04357v1
+2020-12-14,Effect of magnon decays on parametrically pumped magnons,"We investigate the influence of magnon decays on the non-equilibrium dynamics
+of parametrically excited magnons in the magnetic insulator yttrium-iron garnet
+(YIG). Our investigations are motivated by a recent experiment by Noack et al.
+[Phys. Status Solidi B 256, 1900121 (2019)] where an enhancement of the spin
+pumping effect in YIG was observed near the magnetic field strength where
+magnon decays via confluence of magnons becomes kinematically possible. To
+explain the experimental findings, we have derived and solved kinetic equations
+for the non-equilibrium magnon distribution. The effect of magnon decays is
+taken into account microscopically via collision integrals derived from
+interaction vertices involving three powers of magnon operators. Our results
+agree quantitatively with the experimental data.",2012.07870v2
+2021-03-12,Temperature dependence of the interface spin Seebeck effect,"We performed temperature-dependent optical pump - THz emission measurements
+in Y3Fe5O12 (YIG)|Pt from 5 K to room temperature in the presence of an
+externally applied magnetic field. We study the temperature dependence of the
+spin Seebeck effect and observe a continuous increase as temperature is
+decreased, opposite to what is observed in electrical measurements where the
+spin Seebeck effect is suppressed as 0K is approached. By quantitatively
+analysing the different contributions we isolate the temperature dependence of
+the spin-mixing conductance and observe features that are correlated to the
+bands of magnon spectrum in YIG.",2103.07307v1
+2021-03-19,Remote magnon entanglement between two massive ferrimagnetic spheres via cavity optomagnonics,"Recent studies show that hybrid quantum systems based on magnonics provide a
+new and promising platform for generating macroscopic quantum states involving
+a large number of spins. Here we show how to entangle two magnon modes in two
+massive yttrium-iron-garnet (YIG) spheres using cavity optomagnonics, where
+magnons couple to high-quality optical whispering gallery modes supported by
+the YIG sphere. The spheres can be as large as 1 mm in diameter and each sphere
+contains more than $10^{18}$ spins. The proposal is based on the asymmetry of
+the Stokes and anti-Stokes sidebands generated by the magnon-induced Brillouin
+light scattering in cavity optomagnonics. This allows one to utilize the Stokes
+and anti-Stokes scattering process, respectively, for generating and verifying
+the entanglement. Our work indicates that cavity optomagnonics could be a
+promising system for preparing macroscopic quantum states.",2103.10595v2
+2021-04-22,Theory for electrical detection of the magnon Hall effect induced by dipolar interactions,"We derive the anomalous Hall contributions arising from dipolar interactions
+to diffusive spin transport in magnetic insulators. Magnons, the carriers of
+angular momentum in these systems, are shown to have a non-zero Berry
+curvature, resulting in a measurable Hall effect. For yttrium iron garnet (YIG)
+thin films we calculate both the anomalous and magnon spin conductivities. We
+show that for a magnetic field perpendicular to the film the anomalous Hall
+conductivity is finite. This results in a non-zero Hall signal, which can be
+measured experimentally using Permalloy strips arranged like a Hall bar on top
+of the YIG thin film. We show that electrical detection and injection of spin
+is possible, by solving the resulting diffusion-relaxation equation for a Hall
+bar. We predict the experimentally measurable Hall coefficient for a range of
+temperatures and magnetic field strengths. Most strikingly, we show that there
+is a sign change of the Hall coefficient associated with increasing the
+thickness of the film.",2104.11304v1
+2021-04-26,Cavity magnomechanical storage and retrieval of quantum states,"We show how a quantum state in a microwave cavity mode can be transferred to
+and stored in a phononic mode via an intermediate magnon mode in a
+magnomechanical system. For this we consider a ferrimagnetic yttrium iron
+garnet (YIG) sphere inserted in a microwave cavity, where the microwave and
+magnon modes are coupled via a magnetic-dipole interaction and the magnon and
+phonon modes in the YIG sphere are coupled via magnetostrictive forces. By
+modulating the cavity and magnon detunings and the driving of the magnon mode
+in time, a Stimulated Raman Adiabatic Passage (STIRAP)-like coherent transfer
+becomes possible between the cavity mode and the phonon mode. The phononic mode
+can be used to store the photonic quantum state for long periods as it
+possesses lower damping than the photonic and magnon modes. Thus our proposed
+scheme offers a possibility of using magnomechanical systems as quantum memory
+for photonic quantum information.",2104.12323v1
+2021-10-09,Single-shot imaging of ultrafast all-optical magnetization dynamics with a spatio-temporal resolution,"We present a laboratory system for single-shot magneto-optical (MO) imaging
+of ultrafast magnetization dynamics with high-sensitivity of MO rotation. We
+create a stack of MO images repeatedly employing a single pair of a pump and
+defocused probe pulses to induce and visualize MO changes in the sample. Both
+laser beams are independently wavelength-tunable allowing for a flexible,
+resonant adjustable two-color pump and probe scheme. To increase the MO
+contrast the probe beam is spatially filtered. We performed the all-optical
+switching experiment in Co-doped yttrium iron garnet films (YIG:Co) to
+demonstrate the capability of the presented method. We determine the
+spatial-temporal distribution of the effective field of photo-induced
+anisotropy driving the all-optical switching of the magnetization in YIG:Co
+film without an external magnetic field. Moreover, using this imaging method,
+we tracked the process of the laser-induced magnetization precession.",2110.04506v1
+2021-12-30,Giant magnon spin conductivity approaching the two-dimensional transport regime in ultrathin yttrium iron garnet films,"Conductivities are key material parameters that govern various types of
+transport (electronic charge, spin, heat etc.) driven by thermodynamic forces.
+Magnons, the elementary excitations of the magnetic order, flow under the
+gradient of a magnon chemical potential in proportion to a magnon (spin)
+conductivity $\sigma_{m}$. The magnetic insulator yttrium iron garnet (YIG) is
+the material of choice for efficient magnon spin transport. Here we report an
+unexpected giant $\sigma_{m}$ in record-thin YIG films with thicknesses down to
+3.7 nm when the number of occupied two-dimensional (2D) subbands is reduced
+from a large number to a few, which corresponds to a transition from 3D to 2D
+magnon transport. We extract a 2D spin conductivity ($\approx1$ S) at room
+temperature, comparable to the (electronic) spin conductivity of the
+high-mobility two-dimensional electron gas in GaAs quantum wells at millikelvin
+temperatures. Such high conductivities offer unique opportunities to develop
+low-dissipation magnon-based spintronic devices.",2112.15165v3
+2022-01-16,Coherent coupling of two remote magnonic resonators mediated by superconducting circuits,"We demonstrate microwave-mediated distant magnon-magnon coupling on a
+superconducting circuit platform, incorporating chip-mounted single-crystal
+Y$_3$Fe$_5$O$_{12}$ (YIG) spheres. Coherent level repulsion and dissipative
+level attraction between the magnon modes of the two YIG spheres are
+demonstrated. The former is mediated by cavity photons of a superconducting
+resonator, and the latter is mediated by propagating photons of a coplanar
+waveguide. Our results open new avenues towards exploring integrated hybrid
+magnonic networks for coherent information processing on a quantum-compatible
+superconducting platform.",2201.05937v1
+2022-03-08,Interplay between nonlinear spectral shift and nonlinear damping of spin waves in ultrathin YIG waveguides,"We use the phase-resolved imaging to directly study the nonlinear
+modification of the wavelength of spin waves propagating in 100-nm thick,
+in-plane magnetized YIG waveguides. We show that, by using moderate microwave
+powers, one can realize spin waves with large amplitudes corresponding to
+precession angles in excess of 10 degrees and nonlinear wavelength variation of
+up to 18 percent in this system. We also find that, at large precession angles,
+the propagation of spin waves is strongly affected by the onset of nonlinear
+damping, which results in a strong spatial dependence of the wavelength. This
+effect leads to a spatially dependent controllability of the wavelength by the
+microwave power. Furthermore, it leads to the saturation of nonlinear spectral
+shift's effects several micrometers away from the excitation point. These
+findings are important for the development of nonlinear, integrated spin-wave
+signal processing devices and can be used to optimize their characteristics.",2203.04018v1
+2022-03-15,Standing spin wave excitation in Bi:YIG films via temperature induced anisotropy changes and magnetoacoustic coupling,"Based on micromagnetic simulations and experimental observations of the
+magnetization and lattice dynamics following the direct optical excitation of
+the magnetic insulator Bi:YIG or indirect excitation via an optically opaque
+Pt/Cu double layer, we disentangle the dynamical effects of magnetic anisotropy
+and magnetoelastic coupling. The strain and temperature of the lattice are
+quantified via modeling ultrafast x-ray diffraction data. Measurements of the
+time-resolved magneto-optical Kerr effect agree well with the magnetization
+dynamics simulated according to the excitation via two mechanisms: The
+magneto-acoustic coupling to the experimentally verified strain dynamics and
+the ultrafast temperature-induced transient change in the magnetic anisotropy.
+The numerical modeling proves that for direct excitation both mechanisms drive
+the fundamental mode with opposite phase. The relative ratio of standing
+spin-wave amplitudes of higher order modes indicates that both mechanisms are
+substantially active.",2203.07851v1
+2022-06-09,Magnetically tunable zero-index metamaterials,"Zero-index metamaterials (ZIMs) feature a uniform electromagnetic mode over a
+large area in arbitrary shapes, enabling many applications including
+high-transmission supercouplers with arbitrary shapes, direction-independent
+phase matching for nonlinear optics, and collective emission of many quantum
+emitters. However, most ZIMs reported till date are passive, with no method for
+the dynamic modulation of their electromagnetic properties. Here, we design and
+fabricate a magnetically tunable ZIM consisting of yttrium iron garnet (YIG)
+pillars sandwiched between two copper clad laminates in the microwave regime.
+By harnessing the Cotton-Mouton effect of YIG, the metamaterial was
+successfully toggled between gapless and bandgap states, leading to a ""phase
+transition"" between a zero-index phase and a single negative phase of the
+metamaterial. Using an S-shaped ZIM supercoupler, we experimentally
+demonstrated a tunable supercoupling state with a low intrinsic loss of 0.95 dB
+and a high extinction ratio of up to 30.63 dB at 9 GHz. Our work enables
+dynamic modulation of the electromagnetic characteristics of ZIMs, enabling
+various applications in tunable linear, nonlinear, quantum and nonreciprocal
+electromagnetic devices.",2206.04237v1
+2022-06-29,Spin-Wave Optics in YIG by Ion-Beam Irradiation,"We demonstrate direct focused ion beam (FIB) writing as an enabling
+technology for realizing spin-wave-optics devices. It is shown that ion-beam
+irradiation changes the characteristics of YIG films on a submicron scale in a
+highly controlled way, allowing to engineer the magnonic index of refraction
+adapted to desired applications. This technique does not physically remove
+material, and allows rapid fabrication of high-quality architectures of
+modified magnetization in magnonic media with minimal edge damage (compared to
+more common techniques such as etching or milling). By experimentally showing
+magnonic versions of a number of optical devices (lenses, gratings,
+Fourier-domain processors) we envision this technology as the gateway to
+building magnonic computing devices that rival their optical counterparts in
+their complexity and computational power.",2206.14696v1
+2022-09-09,A spinwave Ising machine,"We demonstrate a spin-wave-based time-multiplexed Ising Machine (SWIM),
+implemented using a 5 $\mu$m thick Yttrium Iron Garnet (YIG) film and
+off-the-shelf microwave components. The artificial Ising spins consist of
+34--68 ns long 3.125 GHz spinwave RF pulses with their phase binarized using a
+phase-sensitive microwave amplifier. Thanks to the very low spinwave group
+velocity, the 7 mm long YIG waveguide can host an 8-spin MAX-CUT problem and
+solve it in less than 4 $\mu$s while consuming only 7 $\mu$J. Using a real-time
+oscilloscope, we follow the temporal evolution of each spin as the SWIM
+minimizes its energy and find both uniform and domain-propagation-like
+switching of the spin state. The SWIM has the potential for substantial further
+miniaturization, scalability, speed, and reduced power consumption, and may
+become a versatile platform for commercially feasible optimization problem
+solvers with high performance.",2209.04291v1
+2022-09-21,Interactive Entanglement in Hybrid Opto-magno-mechanics System,"We present a novel cavity opto-magno-mechanical hybrid system to generate
+entanglements among multiple quantum carriers, such as magnons, mechanical
+resonators, and cavity photons in both the optical and microwave domains. Two
+Yttrium iron garnet (YIG) spheres are embedded in two separate microwave
+cavities which are joined by a communal mechanical resonator. Because the
+microwave cavities are separate, the ferromagnetic resonate frequencies of two
+YIG spheres can be tuned independently, as well as the cavity frequencies. We
+show that entanglement can be achieved with experimentally reachable
+parameters. The entanglement is robust against environmental thermal noise,
+owing to the mechanical cooling process achieved by the optical cavity. The
+maximum entanglement among different carriers is achieved by optimizing the
+parameters of the system. The individual tunability of the separated cavities
+allows us to independently control the entanglement properties of different
+subsystems and establish quantum channels with different entanglement
+properties in one system. This work could provide promising applications in
+quantum metrology and quantum information tasks.",2209.10120v2
+2022-09-29,Strong to ultra-strong coherent coupling measurements in a YIG/cavity system at room temperature,"We present an experimental study of the strong to ultra-strong coupling
+regimes at room temperature in frequency-reconfigurable 3D re-entrant cavities
+coupled with a YIG slab. The observed coupling rate, defined as the ratio of
+the coupling strength to the cavity frequency of interest, ranges from 12% to
+59%. We show that certain considerations must be taken into account when
+analyzing the polaritonic branches of a cavity spintronic device where the RF
+field is highly focused in the magnetic material. Our observations are in
+excellent agreement with electromagnetic finite element simulations in the
+frequency domain.",2209.14643v2
+2022-10-03,Chirality-induced one-way quantum steering between two waveguide-mediated ferrimagnetic microspheres,"One-way quantum steering is of importance for quantum technologies, such as
+secure quantum teleportation. In this paper, we study the generation of one-way
+quantum steering between two distant yttrium iron garnet (YIG) microspheres in
+chiral waveguide electromagonics. We consider that the magnon mode with the
+Kerr nonlinearity in each YIG sphere is chirally coupled to left- and
+right-propagating guided photons in the waveguide. We find that quantum
+steering between the magnon modes is absent with non-chirality but is present
+merely in the form of one way (i.e., one-way steering) when the chirality
+occurs. The maximal achievable steering is obviously improved as the chirality
+degree increases. We further find that when the waveguide's outputs are
+subjected to continuous homodyne detection, the steering can be considerably
+enhanced and asymmetric steering with strong entanglement can also be achieved
+by tuning the chirality. Our study shows that chirality can be explored to
+effectively realize one-way quantum steering. Compared to other studies on
+achieving asymmetric steering via controlling intrinsic dissipation, e.g.
+cavity loss rates, our scheme merely depends on the chirality enabled via
+positioning the micromagnets in the waveguide and is continuously adjustable
+and experimentally more feasible.",2210.00710v1
+2023-03-02,Unidirectional Microwave Transduction with Chirality Selected Short-Wavelength Magnon Excitations,"Nonreciprocal magnon propagation has recently become a highly potential
+approach of developing chip-embedded microwave isolators for advanced
+information processing. However, it is challenging to achieve large
+nonreciprocity in miniaturized magnetic thin-film devices because of the
+difficulty of distinguishing propagating surface spin waves along the opposite
+directions when the film thickness is small. In this work, we experimentally
+realize unidirectional microwave transduction with sub-micron-wavelength
+propagating magnons in a yttrium iron garnet (YIG) thin film delay line. We
+achieve a non-decaying isolation of 30 dB with a broad field-tunable band-pass
+frequency range up to 14 GHz. The large isolation is due to the selection of
+chiral magnetostatic surface spin waves with the Oersted field generated from
+the coplanar waveguide antenna. Increasing the geometry ratio between the
+antenna width and YIG thickness drastically reduces the nonreciprocity and
+introduces additional magnon transmission bands. Our results pave the way for
+on-chip microwave isolation and tunable delay line with short-wavelength
+magnonic excitations.",2303.00936v1
+2023-05-16,Tunable all-optical logic gates based on nonreciprocal topologically protected edge modes,"All-optical logic gates have been studied intensively for their potential to
+enable broadband, low-loss, and high-speed communication. However, poor
+tunability has remained a key challenge in this field. In this paper, we
+propose a Y-shaped structure composed of Yttrium Iron Garnet (YIG) layers that
+can serve as tunable all-optical logic gates, including, but not limited to,
+OR, AND, and NOT gates, by applying external magnetic fields to magnetize the
+YIG layers. Our findings demonstrate that these logic gates are based on
+topologically protected one-way edge modes, ensuring exceptional robustness
+against imperfections and nonlocal effects while maintaining extremely high
+precision. Furthermore, the operating band of the logic gates is shown to be
+tunable. In addition, we introduce a straightforward and practical method for
+controlling and switching the logic gates between ""work"", ""skip"", and ""stop""
+modes. These findings have important implications for the design of
+high-performance and precise all-optical integrated circuits.",2305.09270v1
+2023-06-07,Gain assisted controllable fast light generation in cavity magnomechanics,"We study the controllable output field generation from a cavity
+magnomechanical resonator system that consists of two coupled microwave
+resonators. The first cavity interacts with a ferromagnetic yttrium iron garnet
+(YIG) sphere providing the magnon-photon coupling. Under passive cavities
+configuration, the system displays high absorption, prohibiting output
+transmission even though the dispersive response is anamolous. We replace the
+second passive cavity with an active one to overcome high absorption, producing
+an effective gain in the system. We show that the deformation of the YIG sphere
+retains the anomalous dispersion. Further, tuning the exchange interaction
+strength between the two resonators leads to the system's effective gain and
+dispersive response. As a result, the advancement associated with the
+amplification of the probe pulse can be controlled in the close vicinity of the
+magnomechanical resonance. Furthermore, we find the existence of an upper bound
+for the intensity amplification and the advancement of the probe pulse that
+comes from the stability condition. These findings may find potential
+applications for controlling light propagation in cavity magnomechanics.",2306.04390v1
+2023-07-19,Zero-field spin waves in YIG nano-waveguides,"Spin-wave based transmission and processing of information is a promising
+emerging nano-technology that can help overcome limitations of traditional
+electronics based on the transfer of electrical charge. Among the most
+important challenges for this technology is the implementation of spin-wave
+devices that can operate without the need for an external bias magnetic field.
+Here we experimentally demonstrate that this can be achieved using
+sub-micrometer wide spin-wave waveguides fabricated from ultrathin films of
+low-loss magnetic insulator - Yttrium Iron Garnet (YIG). We show that these
+waveguides exhibit a highly stable single-domain static magnetic configuration
+at zero field and support long-range propagation of spin waves with gigahertz
+frequencies. The experimental results are supported by micromagnetic
+simulations, which additionally provide information for optimization of
+zero-field guiding structures. Our findings create the basis for the
+development of energy-efficient zero-field spin-wave devices and circuits.",2307.09805v1
+2023-08-25,Giant orbit-to-charge conversion induced via the inverse orbital Hall effect,"We investigate the orbit-to-charge conversion in YIG/Pt/nonmagnetic material
+(NM) trilayer heterostructures. With the additional Ru layer on the top of
+YIG/Pt stacks, the charge current signal increases nearly an order of magnitude
+in both longitudinal spin Seebeck effect (SSE) and spin pumping (SP)
+measurements. Through thickness dependence studies of the Ru metal layer and
+theoretical model, we quantitatively clarify different contributions of the
+increased SSE signal that mainly comes from the inverse orbital Hall effect
+(IOHE) of Ru, and partially comes from the orbital sink effect in the Ru layer.
+A similar enhancement of SSE(SP) signals is also observed when Ru is replaced
+by other materials (Ta, W, and Cu), implying the universality of the IOHE in
+transition metals. Our findings not only suggest a more efficient generation of
+the charge current via the orbital angular moment channel but also provides
+crucial insights into the interplay among charge, spin, and orbit.",2308.13144v1
+2023-08-25,Macroscopic distant magnon modes entanglement via a squeezed reservoir,"The generation of robust entanglement in quantum system arrays is a crucial
+aspect of the realization of efficient quantum information processing.
+Recently, the field of quantum magnonics has garnered significant attention as
+a promising platform for advancing in this direction. In our proposed scheme,
+we utilize a one-dimensional array of coupled cavities, with each cavity
+housing a single yttrium iron garnet (YIG) sphere coupled to the cavity mode
+through magnetic dipole interaction. To induce entanglement between YIGs, we
+employ a local squeezed reservoir, which provides the necessary nonlinearity
+for entanglement generation. Our results demonstrate the successful generation
+of bipartite and tripartite entanglement between distant magnon modes, all
+achieved through a single quantum reservoir. Furthermore, the steady-state
+entanglement between magnon modes is robust against magnon dissipation rates
+and environment temperature. Our results may lead to applications of
+cavity-magnon arrays in quantum information processing and quantum
+communication systems.",2308.13586v3
+2023-08-30,Chiral cavity-magnonic system for the unidirectional emission of a tunable squeezed microwave field,"Unidirectional photon emission is crucial for constructing quantum networks
+and realizing scalable quantum information processing. In the present work an
+efficient scheme is developed for the unidirectional emission of a tunable
+squeezed microwave field. Our scheme is based on a chiral cavity magnonic
+system, where a magnon mode in a single-crystalline yttrium iron garnet (YIG)
+sphere is selectively coupled to one of the two degenerate rotating microwave
+modes in a torus-shaped cavity with the same chirality. With the YIG sphere
+driven by a two-color Floquet field to induce sidebands in the magnon-photon
+coupling, we show that the unidirectional emission of a tunable squeezed
+microwave field can be generated via the assistance of the dissipative magnon
+mode and a waveguide. Moreover, the direction of the proposed one-way emitter
+can be controlled on demand by reversing the biased magnetic field. Our work
+opens up an avenue to create and manipulate one-way nonclassical microwave
+radiation field and could find potential quantum technological applications.",2308.15826v1
+2023-10-29,Magnomechanically controlled Goos-Hänchen shift in cavity QED,"Phenomena involving interactions among magnons, phonons, and photons in
+cavity magnomechanical systems have attracted considerable attention recently,
+owing to their potential applications in the microwave frequency range. One
+such important effect is the response of a probe field to such tripartite
+interaction between photon-magnon-phonon. In this paper, we study
+Goos-H\""{a}nchen shift (GHS) of a reflected probe field in a cavity
+magnomechanical system. We consider a YIG sphere positioned within a microwave
+cavity. A microwave control field directly drives the magnon mode in YIG
+sphere, whereas the cavity is driven via a weak probe field. Our results show
+that the GHS can be coherently controlled through magnon-phonon coupling via
+the control field. For instance, GHS can be tuned from positive to negative by
+tuning the magnon-phonon coupling. Similarly, the effective cavity detuning is
+another important controlling parameter for GHS. Furthermore, we observe that
+the enhancement of GHS occurs when magnon-phonon coupling is weak at resonance,
+and when the magnon-photon coupling is approximately equal to the loss of
+microwave photons. Our findings may have potential significance in applications
+related to microwave switching and sensing.",2310.19111v1
+2023-11-13,Microwave-to-Optical Quantum Transduction Utilizing the Topological Faraday Effect of Topological Insulator Heterostructures,"The quantum transduction between microwave and optical photons is essential
+for realizing scalable quantum computers with superconducting qubits. Due to
+the large frequency difference between microwave and optical ranges, the
+transduction needs to be done via intermediate bosonic modes or nonlinear
+processes. So far, the transduction efficiency $\eta$ via the magneto-optic
+Faraday effect (i.e., the light-magnon interaction) in the ferromagnet YIG has
+been demonstrated to be small as $\eta\sim 10^{-8} \mathrm{-} 10^{-15}$ due to
+the sample size limitation inside the cavity. Here, we take advantage of the
+fact that three-dimensional topological insulator thin films exhibit a
+topological Faraday effect that is independent of the sample thickness. This
+leads to a large Faraday rotation angle and therefore enhanced light-magnon
+interaction in the thin film limit. We show theoretically that the transduction
+efficiency can be greatly improved to $\eta\sim10^{-4}$ by utilizing the
+heterostructures consisting of topological insulator thin films such as
+Bi$_2$Se$_3$ and ferromagnetic insulator thin films such as YIG.",2311.07293v1
+2023-11-15,Broad-Wavevector Spin Pumping of Flat-Band Magnons,"We report the experimental observation of large spin pumping signals in
+YIG/Pt system driven by broad-wavevector spin-wave spin current. 280 nm-wide
+microwave inductive antennas offer broad-wavevector excitation which, in
+combination with quasi-flatband of YIG, allows a large number of magnons to
+participate in spin pumping at a given frequency. Through comparison with
+ferromagnetic resonance spin pumping, we attribute the enhancement of the spin
+current to the multichromatic magnons. The high efficiency of spin current
+generation enables us to uncover nontrivial propagating properties in ultra-low
+power regions. Additionally, our study achieves the spatially separated
+detection of magnons, allowing the direct extraction of the decay length. The
+synergistic combination of the capability of broad-wavevector excitation,
+enhanced voltage signals, and nonlocal detection provides a new avenue for the
+electrical exploration of spin waves dynamics.",2311.09098v1
+2023-11-25,Spin pumping in YIG-Pt structures: the role of the van Hove singularities,"Spin pumping by surface and backward volume magnetostatic waves in YIG/Pt
+structures is experimentally studied and analyzed. It is shown that at
+frequencies corresponding to van Hove singularities in the density of states of
+the spin wave spectrum, an increase in the efficiency of electron-magnon
+scattering and spin current generation takes place. The obtained results are
+important for spin wave-based spintronic devices development.",2311.15096v1
+2024-02-05,Controlling magnon-photon coupling in a planar geometry,"The tunability of magnons enables their interaction with various other
+quantum excitations, including photons, paving the route for novel hybrid
+quantum systems. Here, we study magnon-photon coupling using a high-quality
+factor split-ring resonator and single-crystal yttrium iron garnet (YIG)
+spheres at room temperature. We investigate the dependence of the coupling
+strength on the size of the sphere and find that the coupling is stronger for
+spheres with a larger diameter as predicted by theory. Furthermore, we
+demonstrate strong magnon-photon coupling by varying the position of the YIG
+sphere within the resonator. Our experimental results reveal the expected
+correlation between the coupling strength and the rf magnetic field. These
+findings demonstrate the control of coherent magnon-photon coupling through the
+theoretically predicted square-root dependence on the spin density in the
+ferromagnetic medium and the magnetic dipolar interaction in a planar
+resonator.",2402.03071v1
+2024-03-12,Negative orbital Hall effect in Germanium,"Our investigation reveals a groundbreaking discovery of a negative inverse
+orbital Hall effect (IOHE) in Ge thin films. We employed the innovative orbital
+pumping technique where spin-orbital coupled current is injected into Ge films
+using YIG/Pt(2)/Ge($t_{Ge}$) and YIG/W(2)/Ge($t_{Ge}$) heterostructures.
+Through comprehensive analysis, we observe significant reductions in the
+signals generated by coherent (RF-driven) and incoherent (thermal-driven)
+spin-orbital pumping techniques. These reductions are attributed to the
+presence of a remarkable strong negative IOHE in Ge, showing its magnitude
+comparable to the spin-to-charge signal in Pt. Our findings reveal that
+although the spin-to-charge conversion in Ge is negligible, the
+orbital-to-charge conversion exhibits large magnitude. Our results are
+innovative and pioneering in the investigation of negative IOHE by the
+injection of spin-orbital currents.",2403.07254v1
+2017-09-21,Electrical properties of single crystal Yttrium Iron Garnet ultra-thin films at high temperatures,"We report a study on the electrical properties of 19 nm thick Yttrium Iron
+Garnet (YIG) films grown by liquid phase epitaxy. The electrical conductivity
+and Hall coefficient are measured in the high temperature range [300,400]~K
+using a Van der Pauw four-point probe technique. We find that the electrical
+resistivity decreases exponentially with increasing temperature following an
+activated behavior corresponding to a band-gap of $E_g\approx 2$ eV, indicating
+that epitaxial YIG ultra-thin films behave as large gap semiconductor, and not
+as electrical insulator. The resistivity drops to about $5\times 10^3$~$\Omega
+\cdot \text{cm}$ at $T=400$ K. We also infer the Hall mobility, which is found
+to be positive ($p$-type) at 5 cm$^2$/(V$\cdot$sec) and about independent of
+temperature. We discuss the consequence for non-local transport experiments
+performed on YIG at room temperature. These electrical properties are
+responsible for an offset voltage (independent of the in-plane field direction)
+whose amplitude, odd in current, grows exponentially with current due to Joule
+heating. These electrical properties also induce a sensitivity to the
+perpendicular component of the magnetic field through the Hall effect. In our
+lateral device, a thermoelectric offset voltage is produced by a temperature
+gradient along the wire direction proportional to the perpendicular component
+of the magnetic field (Righi-Leduc effects).",1709.07207v1
+2019-03-19,Magnetic properties and domain structure of ultrathin yttrium iron garnet/Pt bilayers,"We report on the structure, magnetization, magnetic anisotropy, and domain
+morphology of ultrathin yttrium iron garnet (YIG)/Pt films with thickness
+ranging from 3 to 90 nm. We find that the saturation magnetization is close to
+the bulk value in the thickest films and decreases towards low thickness with a
+strong reduction below 10 nm. We characterize the magnetic anisotropy by
+measuring the transverse spin Hall magnetoresistance as a function of applied
+field. Our results reveal strong easy plane anisotropy fields of the order of
+50-100 mT, which add to the demagnetizing field, as well as weaker in-plane
+uniaxial anisotropy ranging from 10 to 100 $\mu$T. The in-plane easy axis
+direction changes with thickness, but presents also significant fluctuations
+among samples with the same thickness grown on the same substrate. X-ray
+photoelectron emission microscopy reveals the formation of zigzag magnetic
+domains in YIG films thicker than 10 nm, which have dimensions larger than
+several 100 $\mu$m and are separated by achiral N\'{e}el-type domain walls.
+Smaller domains characterized by interspersed elongated features are found in
+YIG films thinner than 10 nm.",1903.08285v1
+2020-05-28,A First Principle Study on Magneto-Optical Effects and Magnetism in Ferromagnetic Semiconductors Y$_3$Fe$_5$O$_{12}$ and Bi$_3$Fe$_5$O$_{12}$,"The magneto-optical (MO) effects not only are a powerful probe of magnetism
+and electronic structure of magnetic solids but also have valuable applications
+in high-density data-storage technology. Yttrium iron garnet
+(Y$_3$Fe$_5$O$_{12}$) (YIG) and bismuth iron garnet (Bi$_3$Fe$_5$O$_{12}$)
+(BIG) are two widely used magnetic semiconductors with strong magneto-optical
+effects and have also attracted the attention for fundamental physics studies.
+In particular, YIG has been routinely used as a spin current injector. In this
+paper, we present a thorough theoretical investigation on magnetism,
+electronic, optical and MO properties of YIG and BIG, based on the density
+functional theory with the generalized gradient approximation plus onsite
+Coulomb repulsion. We find that both semiconductors exhibit large MO effects
+with their Kerr and Faraday rotation angles being comparable to that of
+best-known MO materials such as MnBi. Especially, the MO Kerr rotation angle
+for bulk BIG reaches -1.2$ ^{\circ}$ at photon energy $\sim2.4$ eV, and the MO
+Faraday rotation angle for BIG film reaches -74.6 $ ^{\circ}/\mu m$ at photon
+energy $\sim2.7$ eV. Furthermore, we also find that both valence and conduction
+bands across the MO band gap in BIG are purely spin-down states, i.e., BIG is a
+single spin semiconductor. These interesting findings suggest that the iron
+garnets will find valuable applications in semiconductor MO and spintronic
+nanodevices. The calculated optical conductivity spectra, MO Kerr and Faraday
+rotation angles agree well with the available experimental data. The main
+features in the optical and MO spectra of both systems are analyzed in terms of
+the calculated band structures especially by determining the band state
+symmetries and the main optical transitions at the $\Gamma$ point in the
+Brillouin zone.",2005.14133v2
+2021-05-02,Steady state entanglement of distant nitrogen-vacancy centers in a coherent thermal magnon bath,"We investigate steady-state entanglement (SSE) between two nitrogen-vacancy
+(NV) centers in distant nanodiamonds on an ultrathin Yttrium Iron Garnet (YIG)
+strip. We determine the dephasing and dissipative interactions of the qubits
+with the quanta of spin waves (magnon bath) in the YIG depending on the qubit
+positions on the strip. We show that the magnon's dephasing effect can be
+eliminated, and we can transform the bath into a multimode displaced thermal
+state using external magnetic fields. Entanglement dynamics of the qubits in
+such a displaced thermal bath have been analyzed by deriving and solving the
+master equation. An additional electric field is considered to engineer the
+magnon dispersion relation at the band edge to control the Markovian character
+of the open system dynamics. We determine the optimum geometrical parameters of
+the system of distant qubits and the YIG strip to get SSE. Furthermore,
+parameter regimes for which the shared displaced magnon bath can sustain
+significant SSE against the local dephasing and decoherence of NV centers to
+their nuclear spin environments have been determined. Along with SSE, we
+investigate the steady-state coherence (SSC) and explain the physical mechanism
+of how delayed SSE appears following a rapid generation and sudden death of
+entanglement using the interplay of decoherence-free subspace states, system
+geometry, displacement of the thermal bath, and enhancement of the qubit
+dissipation near the magnon band edge. A non-monotonic relation between bath
+coherence and SSE is found, and critical coherence for maximum SSE is
+determined. Our results illuminate the efficient use of system geometry, band
+edge in bath spectrum, and reservoir coherence to engineer system-reservoir
+interactions for robust SSE and SSC.",2105.00519v2
+2022-10-15,Non-local magnon transconductance in extended magnetic insulating films.\\Part II: two-fluid behavior,"This review presents a comprehensive study of the spatial dispersion of
+propagating magnons electrically emitted in extended yttrium-iron garnet (YIG)
+films by the spin transfer effects across a YIG$\vert$Pt interface. Our goal is
+to provide a generic framework to describe the magnon transconductance inside
+magnetic films. We experimentally elucidate the relevant spectral contributions
+by studying the lateral decay of the magnon signal. While most of the injected
+magnons do not reach the collector, the propagating magnons can be split into
+two-fluids: \textit{i)} a large fraction of high-energy magnons carrying energy
+of about $k_B T_0$, where $T_0$ is the lattice temperature, with a
+characteristic decay length in the sub-micrometer range, and \textit{ii)} a
+small fraction of low-energy magnons, which are particles carrying energy of
+about $\hbar \omega_K$, where $\omega_K/(2 \pi)$ is the Kittel frequency, with
+a characteristic decay length in the micrometer range. Taking advantage of
+their different physical properties, the low-energy magnons can become the
+dominant fluid \textit{i)} at large spin transfer rates for the bias causing
+the emission of magnons, \textit{ii)} at large distance from the emitter,
+\textit{iii)} at small film thickness, or \textit{iv)} for reduced band
+mismatch between the YIG below the emitter and the bulk due to variation of the
+magnon concentration. This broader picture complements part I \cite{kohno_SD},
+which focuses solely on the nonlinear transport properties of low-energy
+magnons.",2210.08283v2
+2023-08-18,"Magnon Diffusion Length and Longitudinal Spin Seebeck Effect in Vanadium Tetracyanoethylene (V[TCNE]$_x$, $x \sim 2$)","Spintronic, spin caloritronic, and magnonic phenomena arise from complex
+interactions between charge, spin, and structural degrees of freedom that are
+challenging to model and even more difficult to predict. This situation is
+compounded by the relative scarcity of magnetically-ordered materials with
+relevant functionality, leaving the field strongly constrained to work with a
+handful of well-studied systems that do not encompass the full phase space of
+phenomenology predicted by fundamental theory. Here we present an important
+advance in this coupled theory-experiment challenge, wherein we extend existing
+theories of the spin Seebeck effect (SSE) to explicitly include the
+temperature-dependence of magnon non-conserving processes. This expanded theory
+quantitatively describes the low-temperature behavior of SSE signals previously
+measured in the mainstay material yttrium iron garnet (YIG) and predicts a new
+regime for magnonic and spintronic materials that have low saturation
+magnetization, $M_S$, and ultra-low damping. Finally, we validate this
+prediction by directly observing the spin Seebeck resistance (SSR) in the
+molecule-based ferrimagnetic semiconductor vanadium tetracyanoethylene
+(V[TCNE]$_x$, $x \sim 2$). These results validate the expanded theory, yielding
+SSR signals comparable in magnitude to YIG and extracted magnon diffusion
+length ($\lambda_m>1$ $\mu$ m) and magnon lifetime for V[TCNE]$_x$
+($\tau_{th}\approx 1-10$ $\mu$ s) exceeding YIG ($\tau_{th}\sim 10$ ns).
+Surprisingly, these properties persist to room temperature despite relatively
+low spin wave stiffness (exchange). This identification of a new regime for
+highly efficient SSE-active materials opens the door to a new class of magnetic
+materials for spintronic and magnonic applications.",2308.09752v1
+2009-03-02,Magnetooptical control of light collapse in bulk Kerr media,"Magneto-optical crystals allow an efficient control of the birefringence of
+light via the Cotton-Mouton and Faraday effects. These effects enable a unique
+combination of adjustable linear and circular birefringence, which, in turn,
+can affect the propagation of light in nonlinear Kerr media. We show
+numerically that the combined birefringences can accelerate, delay, or arrest
+the nonlinear collapse of (2+1)D beams, and report an experimental observation
+of the acceleration of the onset of collapse in a bulk Yttrium Iron Garnet
+(YIG) crystal in an external magnetic field.",0903.0373v1
+2011-03-19,Spin transfer torque on magnetic insulators,"Recent experimental and theoretical studies focus on spin-mediated heat
+currents at interfaces between normal metals and magnetic insulators. We
+resolve conflicting estimates for the order of magnitude of the spin transfer
+torque by first-principles calculations. The spin mixing conductance
+G^\uparrow\downarrow of the interface between silver and the insulating
+ferrimagnet Yttrium Iron Garnet (YIG) is dominated by its real part and of the
+order of 10^14 \Omega^-1m^-2, i.e. close to the value for intermetallic
+interface, which can be explained by a local spin model.",1103.3764v2
+2011-07-06,Spin Seebeck Effect: Amplification of Spin Waves by Thermal Torque,"We observe amplification of spin-wave packets propagating along a film of
+yttrium iron garnet (YIG) subject to a transverse temperature gradient. The
+amplification is attributed to a spin-transfer thermal torque created by spin
+currents generated by means of the spin Seebeck effect that acts on the
+magnetization and opposes the relaxation. The experimental data are interpreted
+with a simple theoretical model using spin-wave theory that gives an
+amplification gain in very good agreement with measurements.",1107.1271v2
+2013-09-11,Nanomechanical AC Susceptometry of an Individual Mesoscopic Ferrimagnet,"A novel method for simultaneous detection of both DC and time-dependent
+magnetic signatures in individual mesoscopic structures has emerged from early
+studies in spin mechanics. Multifrequency nanomechanical detection of AC
+susceptibility and its harmonics highlights reversible nonlinearities in the
+magnetization response of a single yttrium iron garnet (YIG) element,
+separating them from hysteretic jumps in the DC magnetization.",1309.2965v1
+2013-11-12,Nonreciprocity engineering in magnetostatic spin waves,"Magnetostatic surface spin waves (MSSW) excited from a coplanar waveguide
+antenna travel in different directions with different amplitudes. This effect,
+called nonreciprocity of MSSW, has been investigated by micromagnetic
+simulations. The ratio of amplitude of two counter propagating spin waves, the
+nonreciprocity parameter {\kappa}, is obtained for different ferromagnetic
+materials, such as NiFe (Py), CoFeAl, yttrium iron garnet (YIG), and GaMnAs. A
+device schematic has been proposed in which {\kappa} can be tuned to a large
+value by varying simple geometrical parameters of the device.",1311.2686v1
+2014-04-09,Current-induced spin torque resonance of magnetic insulators,"We formulate a theory of the AC spin Hall magnetoresistance (SMR) in a
+bilayer system consisting of a magnetic insulator such as yttrium iron garnet
+(YIG) and a heavy metal such as platinum (Pt). We derive expressions for the DC
+voltage generation based on the drift-diffusion spin model and quantum
+mechanical boundary condition at the interface that reveal a spin torque
+ferromagnetic resonance (ST-FMR). We predict that ST-FMR experiments will
+reveal valuable information on the current-induced magnetization dynamics of
+magnetic insulators and AC spin Hall effect.",1404.2360v2
+2014-07-18,Microwave-induced spin currents in ferromagnetic-insulator|normal-metal bilayer system,"A microwave technique is employed to simultaneously examine the spin pumping
+and the spin Seebeck effect processes in a YIG|Pt bilayer system. The
+experimental results show that for these two processes, the spin current flows
+in opposite directions. The temporal dynamics of the longitudinal spin Seebeck
+effect exhibits that the effect depends on the diffusion of bulk
+thermal-magnons in the thermal gradient in the
+ferromagnetic-insulator|normal-metal system.",1407.4957v2
+2015-06-09,Identification of spin wave modes strongly coupled to a co-axial cavity,"We demonstrate, at room temperature, the strong coupling of the fundamental
+and non-uniform magnetostatic modes of an yttrium iron garnet (YIG)
+ferrimagnetic sphere to the electromagnetic modes of a co-axial cavity. The
+well-defined field profile within the cavity yields a specific coupling
+strength for each magnetostatic mode. We experimentally measure the coupling
+strength for the different magnetostatic modes and, by calculating the expected
+coupling strengths, are able to identify the modes themselves.",1506.02902v1
+2015-09-15,Magnetic Nernst effect,"The thermodynamics of irreversible processes in continuous media predicts the
+existence of a Magnetic Nernst effect that results from a magnetic analog to
+the Seebeck effect in a ferromagnet and magnetophoresis occurring in a
+paramagnetic electrode in contact with the ferromagnet. Thus, a voltage that
+has DC and AC components is expected across a Pt electrode as a response to the
+inhomogeneous magnetic induction field generated by magnetostatic waves of an
+adjacent YIG slab subject to a temperature gradient. The voltage frequency and
+dependence on the orientation of the applied magnetic induction field are quite
+distinct from that of spin pumping.",1509.04440v1
+2017-02-02,Magnon Condensation and Spin Superfluidity,"We consider the phenomenon of Bose-Einstein condensation of quasi-equilibrium
+magnons which leads to a spin superfluidity, the coherent quantum transfer of
+magnetization in magnetic materials. These phenomena are beyond the classical
+Landau-Lifshitz-Gilbert paradigm. The critical conditions for excited magnon
+density for ferro- and antiferromagnets, bulk and thin films are estimated and
+discussed. The BEC should occur in the antiferromagnetic hematite at much lower
+excited magnon density compared to the ferromagnetic YIG.",1702.00846v2
+2023-07-18,"Propagation of Coupled Acoustic, Electromagnetic and Spin Waves in Saturated Ferromagnetoelastic Solids","We study the propagation of plane waves in an unbounded body of a saturated
+ferromagnetoelastic solid. The equations by Tiersten for small fields
+superposed on finite initial fields in a saturated ferromagnetoelastic material
+are employed, with their quasistatic magnetic field extended to dynamic
+electric and magnetic fields for electromagnetic waves. Dispersion relations of
+the plane waves are obtained. The cutoff frequencies and long wave
+approximation of the dispersion curves are determined. Results show that
+acoustic, electromagnetic and magnetic spin waves are coupled in such a
+material. For YIG which is a cubic crystal without piezoelectric coupling, the
+acoustic and electromagnetic waves are not directly coupled but they can still
+interact indirectly through spin waves.",2307.09171v1
+2023-12-05,Interplay between magnetism and superconductivity in a hybrid magnon-photon bilayer system,"Spin waves in magnetic films are affected by the vicinity to a
+superconductor. Here we studied a bilayer stack made of an insulating Yttrium
+Iron Garnet (YIG) film and a high-$T_c$ YBCO superconducting planar resonator.
+We investigated the hybridization of magnon and photon modes reporting the
+temperature evolution of microwave transmission spectra. Data analysis, based
+on the description of magnon modes and on the Hopfield model, shows that the
+magnon-photon coupling strength and the mode frequency shift can be ultimately
+related to the temperature dependence of the penetration depth of YBCO.",2312.02785v2
+2004-05-26,Microwave Magnetoelectric Effects in Single Crystal Bilayers of Yttrium Iron Garnet and Lead Magnesium Niobate-Lead Titanate,"The first observation of microwave magnetoelectric (ME) interactions through
+ferromagnetic resonance (FMR) in bilayers of single crystal
+ferromagnetic-piezoelectric oxides and a theoretical model for the effect are
+presented. An electric field E produces a mechanical deformation in the
+piezoelectric phase, resulting in a shift dHE in the resonance field for the
+ferromagnet. The strength of ME coupling is obtained from data on dHE vs E.
+Studies were performed at 9.3 GHz on bilayers of (111) yttrium iron garnet
+(YIG) films and (001) lead magnesium niobate-lead titanate (PMN-PT). The
+samples were positioned outside a TE102-reflection type cavity. Resonance
+profiles were obtained for E = 0-8 kV/cm for both in-plane and out-of-plane
+magnetic fields H. Important results are as follows. (i) The ME coupling in the
+bilayers is an order of magnitude stronger than in polycrystalline composites
+and is in the range 1-5.4 Oe cm/kOe, depending on the YIG film thickness. (ii)
+The coupling strength is dependent on the magnetic field orientation and is
+higher for out-of-plane H than for in-plane H. (iii) Estimated ME constant and
+its dependence on volume ratio for the two phases are in good agreement with
+the data.",0405622v1
+2014-08-13,High Cooperativity Cavity QED with Magnons at Microwave Frequencies,"Using a sub-millimetre sized YIG (Yttrium Iron Garnet) sphere mounted in a
+magnetic field-focusing cavity, we demonstrate an ultra-high cooperativity of
+$10^5$ between magnon and photon modes at millikelvin temperatures and
+microwave frequencies. The cavity is designed to act as a magnetic dipole by
+using a novel multiple-post approach, effectively focusing the cavity magnetic
+field within the YIG crystal with a filling factor of 3%. Coupling strength
+(normal-mode splitting) of 2 GHz, (equivalent to 76 cavity linewidths or $0.3$
+Hz per spin), is achieved for a bright cavity mode that constitutes about 10%
+of the photon energy and shows that ultra-strong coupling is possible in spin
+systems at microwave frequencies. With straight forward optimisations we
+demonstrate that with that this system has the potential to reach
+cooperativities of $10^7$, corresponding to a normal mode splitting of 5.2 GHz
+and a coupling per spin approaching 1 Hz. We also observe a three-mode strong
+coupling regime between a dark cavity mode and a magnon mode doublet pair,
+where the photon-magnon and magnon-magnon couplings (normal-mode splittings)
+are 143 MHz and 12.5 MHz respectively, with HWHM bandwidth of about 0.5 MHz.",1408.2905v3
+2015-08-19,Independent tuning of electronic properties and induced ferromagnetism in topological insulators with heterostructure approach,"The quantum anomalous Hall effect (QAHE) has been recently demonstrated in
+Cr- and V-doped three-dimensional topological insulators (TIs) at temperatures
+below 100 mK. In those materials, the spins of unfilled d-electrons in the
+transition metal dopants are exchange coupled to develop a long-range
+ferromagnetic order, which is essential for realizing QAHE. However, the
+addition of random dopants does not only introduce excess charge carriers that
+require readjusting the Bi/Sb ratio, but also unavoidably introduces
+paramagnetic spins that can adversely affect the chiral edge transport in QAHE.
+In this work, we show a heterostructure approach to independently tune the
+electronic and magnetic properties of the topological surface states in
+(BixSb1-x)2Te3 without resorting to random doping of transition metal elements.
+In heterostructures consisting of a thin (BixSb1-x)2Te3 TI film and yttrium
+iron garnet (YIG), a high Curie temperature (~ 550 K) magnetic insulator, we
+find that the TI surface in contact with YIG becomes ferromagnetic via
+proximity coupling which is revealed by the anomalous Hall effect (AHE). The
+Curie temperature of the magnetized TI surface ranges from 20 to 150 K but is
+uncorrelated with the Bi fraction x in (BixSb1-x)2Te3. In contrast, as x is
+varied, the AHE resistivity scales with the longitudinal resistivity. In this
+approach, we decouple the electronic properties from the induced ferromagnetism
+in TI. The independent optimization provides a pathway for realizing QAHE at
+higher temperatures, which is important for novel spintronic device
+applications.",1508.04719v1
+2016-08-29,Sub-micrometer yttrium iron garnet LPE films with low ferromagnetic resonance losses,"Using liquid phase epitaxy (LPE) technique (111) yttrium iron garnet (YIG)
+films with thicknesses of ~100 nm and surface roughnesses as low as 0.3 nm have
+been grown as a basic material for spin-wave propagation experiments in
+microstructured waveguides. The continuously strained films exhibit nearly
+perfect crystallinity without significant mosaicity and with effective lattice
+misfits of delta a(perpendicular)/a(substrate) ~10-4 and below. The
+film/substrate interface is extremely sharp without broad interdiffusion layer
+formation. All LPE films exhibit a nearly bulk-like saturation magnetization of
+(1800+-20) Gs and an `easy cone' anisotropy type with extremely small in-plane
+coercive fields <0.2 Oe. There is a rather weak in-plane magnetic anisotropy
+with a pronounced six-fold symmetry observed for saturation field <1.5 Oe. No
+significant out-of-plane anisotropy is observed, but a weak dependence of the
+effective magnetization on the lattice misfit is detected. The narrowest
+ferromagnetic resonance linewidth is determined to be 1.4 Oe @ 6.5 GHz which is
+the lowest value reported so far for YIG films of 100 nm thicknesses and below.
+The Gilbert damping coefficient for investigated LPE films is estimated to be
+close to 1 x 10-4.",1608.08043v1
+2017-02-17,Spin conductance of YIG thin films driven from thermal to subthermal magnons regime by large spin-orbit torque,"We report a study on spin conductance in ultra-thin films of Yttrium Iron
+Garnet (YIG), where spin transport is provided by propagating spin waves, that
+are generated and detected by direct and inverse spin Hall effects in two Pt
+wires deposited on top. While at low current the spin conductance is dominated
+by transport of thermal magnons, at high current, the spin conductance is
+dominated by low-damping non-equilibrium magnons thermalized near the spectral
+bottom by magnon-magnon interaction, with consequent a sensitivity to the
+applied magnetic field and a longer decay length. This picture is supported by
+microfocus Brillouin Light Scattering spectroscopy.",1702.05226v3
+2017-06-14,Nonlocal magnon-polaron transport in yttrium iron garnet,"The spin Seebeck effect (SSE) is observed in magnetic insulator|heavy metal
+bilayers as an inverse spin Hall effect voltage under a temperature gradient.
+The SSE can be detected nonlocally as well, viz. in terms of the voltage in a
+second metallic contact (detector) on the magnetic film, spatially separated
+from the first contact that is used to apply the temperature bias (injector).
+Magnon-polarons are hybridized lattice and spin waves in magnetic materials,
+generated by the magnetoelastic interaction. Kikkawa et al. [Phys. Rev. Lett.
+\textbf{117}, 207203 (2016)] interpreted a resonant enhancement of the local
+SSE in yttrium iron garnet (YIG) as a function of the magnetic field in terms
+of magnon-polaron formation. Here we report the observation of magnon-polarons
+in \emph{nonlocal} magnon spin injection/detection devices for various
+injector-detector spacings and sample temperatures. Unexpectedly, we find that
+the magnon-polaron resonances can suppress rather than enhance the nonlocal
+SSE. Using finite element modelling we explain our observations as a
+competition between the SSE and spin diffusion in YIG. These results give
+unprecedented insights into the magnon-phonon interaction in a key magnetic
+material.",1706.04373v1
+2017-08-06,Electric-field-induced extremely large change in resistance in graphene ferromagnets,"A colossal magnetoresistance ($\sim 100\times10^3\%$) and an extremely large
+magnetoresistance ($\sim 1\times10^6\%$) have been previously explored in
+manganite perovskites and Dirac materials, respectively. However, the
+requirement of an extremely strong magnetic field (and an extremely low
+temperature) makes them not applicable for realistic devices. In this work, we
+propose a device that can generate even larger changes in resistance in a
+zero-magnetic field and at a high temperature. The device is composed of a
+graphene under two strips of yttrium iron garnet (YIG), where two gate voltages
+are applied to cancel the heavy charge doping in the YIG-induced half-metallic
+ferromagnets. By calculations using the Landauer-B\""{u}ttiker formalism, we
+demonstrate that, when a proper gate voltage is applied on the free
+ferromagnet, changes in resistance up to $305\times10^6\%$ ($16\times10^3\%$)
+can be achieved at the liquid helium (nitrogen) temperature and in a zero
+magnetic field. We attribute such a remarkable effect to a gate-induced
+full-polarization reversal in the free ferromagnet, which results in a
+metal-state to insulator-state transition in the device. We also find that, the
+proposed effect can be realized in devices using other magnetic insulators such
+as EuO and EuS. Our work should be helpful for developing a realistic switching
+device that is energy saving and CMOS-technology compatible.",1708.01858v2
+2017-09-19,Criteria for accurate determination of the magnon relaxation length from the nonlocal spin Seebeck effect,"The nonlocal transport of thermally generated magnons not only unveils the
+underlying mechanism of the spin Seebeck effect, but also allows for the
+extraction of the magnon relaxation length ($\lambda_m$) in a magnetic
+material, the average distance over which thermal magnons can propagate. In
+this study, we experimentally explore in yttrium iron garnet (YIG)/platinum
+systems much further ranges compared with previous investigations. We observe
+that the nonlocal SSE signals at long distances ($d$) clearly deviate from a
+typical exponential decay. Instead, they can be dominated by the nonlocal
+generation of magnon accumulation as a result of the temperature gradient
+present away from the heater, and decay geometrically as $1/d^2$. We emphasize
+the importance of looking only into the exponential regime (i.e., the
+intermediate distance regime) to extract $\lambda_m$. With this principle, we
+study $\lambda_m$ as a function of temperature in two YIG films which are 2.7
+and 50 $\mu$m in thickness, respectively. We find $\lambda_m$ to be around 15
+$\mu$m at room temperature and it increases to 40 $\mu$m at $T=$ 3.5 K. Finite
+element modeling results agree with experimental studies qualitatively, showing
+also a geometrical decay beyond the exponential regime. Based on both
+experimental and modeling results we put forward a general guideline for
+extracting $\lambda_m$ from the nonlocal spin Seebeck effect.",1709.06321v1
+2018-06-04,Large spin-mixing conductance in highly Bi-doped Cu thin films,"Spin Hall effect provides an efficient tool for the conversion of a charge
+current into a spin current, opening the possibility of producing pure spin
+currents in non-magnetic materials for the next generation of spintronics
+devices. In this sense, giant Spin Hall Effect has been recently reported in Cu
+doped with 0.5 % Bi grown by sputtering and larger values are expected for
+larger Bi doping, according to first principles calculations. In this work we
+demonstrate the possibility of doping Cu with up to 10 % of Bi atoms without
+evidences of Bi surface segregation or cluster formation, as studied by
+different microscopic and spectroscopic techniques. In addition, YIG/BiCu
+structures have been grown, showing a spin mixing conductance larger that the
+one shown by similar Pt/YIG structures. These results reflects the potentiality
+of these new materials in spintronics devices.",1806.01394v2
+2019-05-29,Coherent long-range transfer of angular momentum between magnon Kittel modes by phonons,"We report ferromagnetic resonance in the normal configuration of an
+electrically insulating magnetic bilayer consisting of two yttrium iron garnet
+(YIG) films epitaxially grown on both sides of a 0.5-mm-thick nonmagnetic
+gadolinium gallium garnet (GGG) slab. An interference pattern is observed and
+it is explained as the strong coupling of the magnetization dynamics of the two
+YIG layers either in phase or out of phase by the standing transverse sound
+waves, which are excited through a magnetoelastic interaction. This coherent
+mediation of angular momentum by circularly polarized phonons through a
+nonmagnetic material over macroscopic distances can be useful for future
+information technologies.",1905.12523v3
+2019-09-30,Switching the Optical Chirality in Magneto-plasmonic Metasurfaces Using Applied Magnetic Fields,"Chiral nanophotonic devices are promising candidates for chiral molecules
+sensing, polarization diverse nanophotonics and display technologies. Active
+chiral nanophotonic devices, where the optical chirality can be controlled by
+an external stimulus has triggered great research interest. However, efficient
+modulation of the optical chirality has been challenging. Here, we demonstrate
+switching of the extrinsic chirality by applied magnetic fields in a
+magneto-plasmonic metasurface device based on a magneto-optical oxide material,
+Ce1Y2Fe5O12 (Ce:YIG). Thanks to the low optical loss and strong magneto-optical
+effect of Ce:YIG, we experimentally demonstrated a giant and continuous
+far-field circular dichroism (CD) modulation by applied magnetic fields from
+-0.65{\deg} to +1.9{\deg} at 950 nm wavelength under glancing incident
+conditions. The far field CD modulation is due to both magneto-optical circular
+dichroism and near-field modulation of the superchiral fields by applied
+magnetic fields. Finally, we demonstrate magnetic field tunable chiral imaging
+in millimeter-scale magneto-plasmonic metasurfaces fabricated using
+self-assembly. Our results provide a new way for achieving planar integrated,
+large-scale and active chiral metasurfaces for polarization diverse
+nanophotonics.",1909.13605v1
+2019-10-19,Propagation of spin-waves packets in individual nano-sized yttrium iron garnet magnonic conduits,"Modern-days CMOS-based computation technology is reaching its fundamental
+limitations. The emerging field of magnonics, which utilizes spin waves for
+data transport and processing, proposes a promising path to overcome these
+limitations. Different devices have been demonstrated recently on the macro-
+and microscale, but the feasibility of the magnonics approach essentially
+relies on the scalability of the structure feature size down to an extent of a
+few 10 nm, which are typical sizes for the established CMOS technology. Here,
+we present a study of propagating spin-wave packets in individual yttrium iron
+garnet (YIG) conduits with lateral dimensions down to 50 nm. Space and time
+resolved micro-focused Brillouin-Light-Scattering (BLS) spectroscopy is used to
+characterize the YIG nanostructures and measure the spin-wave decay length and
+group velocity directly. The revealed magnon transport at the scale comparable
+to the scale of CMOS proves the general feasibility of a magnon-based data
+processing.",1910.08801v2
+2020-02-27,High-temperature Anomalous Hall Effect in Transition Metal Dichalcogenide-Ferromagnetic Insulator Heterostructure,"Integration of transition metal dichalcogenides (TMDs) on ferromagnetic
+materials (FM) may yield fascinating physics and promise for electronics and
+spintronic applications. In this work, high-temperature anomalous Hall effect
+(AHE) in the TMD ZrTe2 thin film using heterostructure approach by depositing
+it on ferrimagnetic insulator YIG (Y3Fe5O12, yttrium iron garnet) is
+demonstrated. In this heterostructure, significant anomalous Hall effect can be
+observed at temperatures up to at least 400 K, which is a record high
+temperature for the observation of AHE in TMDs, and the large RAHE is more than
+one order of magnitude larger than those previously reported value in
+topological insulators or TMDs based heterostructures. The magnetization of
+interfacial reaction-induced ZrO2 between YIG and ZrTe2 is believed to play a
+crucial role for the induced high-temperature anomalous Hall effect in the
+ZrTe2. These results reveal a promising system for the room-temperature
+spintronic device applications, and it may also open a new avenue toward
+introducing magnetism to TMDs and exploring the quantum AHE at higher
+temperatures considering the prediction of nontrivial topology in ZrTe2.",2002.12068v1
+2020-06-18,Current-induced in-plane magnetization switching in biaxial ferrimagnetic insulator,"Ferrimagnetic insulators (FiMI) have been intensively used in microwave and
+magneto-optical devices as well as spin caloritronics, where their
+magnetization direction plays a fundamental role on the device performance. The
+magnetization is generally switched by applying external magnetic fields. Here
+we investigate current-induced spin-orbit torque (SOT) switching of the
+magnetization in Y3Fe5O12 (YIG)/Pt bilayers with in-plane magnetic anisotropy,
+where the switching is detected by spin Hall magnetoresistance. Reversible
+switching is found at room temperature for a threshold current density of 10^7
+A cm^-2. The YIG sublattices with antiparallel and unequal magnetic moments are
+aligned parallel or antiparallel to the direction of current pulses, which is
+consistent to the Neel order switching in antiferromagnetic system. It is
+proposed that such a switching behavior may be triggered by the
+antidamping-torque acting on the two antiparallel sublattices of FiMI. Our
+finding not only broadens the magnetization switching by electrical means and
+promotes the understanding of magnetization switching, but also paves the way
+for all-electrically modulated microwave devices and spin caloritronics with
+low power consumption.",2006.10313v1
+2020-07-31,Manipulating the photonic Hall effect with hybrid Mie-exciton resonances,"We examine the far-field optical response, under-plane wave excitation in the
+presence of a static magnetic field, of core-shell nanoparticles involving a
+gyroelectric component, either as the inner or the outer layer, through
+analytic calculations based on appropriately extended Mie theory. We focus on
+absorption and scattering of light by bismuth-substituted yttrium iron garnet
+(Bi:YIG) nanospheres and nanoshells, combined with excitonic materials such as
+organic-molecule aggregates or two-dimensional transition-metal
+dichalcogenides, and discuss the hybrid character of the modes emerging from
+the coupling of the two constituents. We observe the excitation of strong
+magneto-optic phenomena and explore, in particular, the response and tunability
+of a magneto-transverse light current, indicative of the photonic Hall effect.
+We show how interaction between the Bi:YIG and excitonic layers leads to a pair
+of narrow bands of highly directional scattering, emerging from the
+aforementioned hybridization, which can be tuned at will by adjusting the
+geometrical or optical parameters of the system. Our theoretical study
+introduces optically anisotropic media as promising templates for strong
+coupling in nanophotonics, offering a means to combine tunable magnetic and
+optical properties, with potential implications both in the design of
+all-dielectric photonic devices but also in novel clinical applications.",2007.16062v2
+2020-08-21,Magnons Parametric Pumping in Bulk Acoustic Waves Resonator,"We report on the experimental observation of excitation and detection of
+parametric spin waves and spin currents in the bulk acoustic wave resonator.
+The hybrid resonator consists of ZnO piezoelectric film, yttrium iron garnet
+(YIG) films on gallium gadolinium garnet substrate, and a heavy metal Pt layer.
+Shear bulk acoustic waves are electrically excited in the ZnO layer due to
+piezoeffect at the resonant frequencies of the resonator. The magnetoelastic
+interaction in the YIG film emerges magnons (spin waves) excitation by acoustic
+waves either on resonator's eigenfrequencies or the half-value frequencies at
+supercritical power. We investigate acoustic pumping of magnons at the
+half-value frequencies and acoustic spin pumping from parametric magnons, using
+the inverse spin Hall effect in the Pt layer. The constant electric voltage in
+the Pt layer, depending on the frequency, the magnetic field, and the pump
+power, was systematically studied. We explain the low threshold obtained (~0.4
+mW) by the high efficiency of electric power transmission into the acoustic
+wave in the resonator.",2008.09520v1
+2020-08-29,Unveiling the polarity of the spin-to-charge current conversion in $Bi_2Se_3$,"We report an investigation of the spin- to charge-current conversion in
+sputter-deposited films of topological insulator $Bi_2Se_{3}$ onto single
+crystalline layers of YIG $(Y_{3}Fe_{5}O_{12})$ and polycrystalline films of
+Permalloy $(Py = Ni_{81}Fe_{19})$. Pure spin current was injected into the
+$Bi_{2}Se_{3}$ layer by means of the spin pumping process in which the spin
+precession is obtained by exciting the ferromagnetic resonance of the
+ferromagnetic film. The spin-current to charge-current conversion, occurring at
+the $Bi_{2}Se_{3}/$ferromagnet interface, was attribute to the inverse
+Rashba-Edelstein effect (IREE). By analyzing the data as a function of the
+$Bi_{2}Se_{3}$ thickness we calculated the IREE length used to characterize the
+efficiency of the conversion process and found that 1.2 pm
+$\leq|{\lambda}_{IREE}|\leq$ 2.2 pm. These results support the fact that the
+surface states of $Bi_{2}Se_{3}$ have a dominant role in the spin-charge
+conversion process, and the mechanism based on the spin diffusion process plays
+a secondary role. We also discovered that the spin- to charge-current mechanism
+in $Bi_{2}Se_{3}$ has the same polarity as the one in Ta, which is the opposite
+to the one in Pt. The combination of the magnetic properties of YIG and Py,
+with strong spin-orbit coupling and dissipationless surface states
+topologically protected of $Bi_{2}Se_{3}$ might lead to spintronic devices with
+fast and efficient spin-charge conversion.",2008.12900v1
+2021-07-14,Frequency fluctuations of ferromagnetic resonances at milliKelvin temperatures,"Unwanted fluctuations over time, in short, noise, are detrimental to device
+performance, especially for quantum coherent circuits. Recent efforts have
+demonstrated routes to utilizing magnon systems for quantum technologies, which
+are based on interfacing single magnons to superconducting qubits. However, the
+coupling of several components often introduces additional noise to the system,
+degrading its coherence. Researching the temporal behavior can help to identify
+the underlying noise sources, which is a vital step in increasing coherence
+times and the hybrid device performance. Yet, the frequency noise of the
+ferromagnetic resonance (FMR) has so far been unexplored. Here, we investigate
+such FMR frequency fluctuations of a YIG sphere down to mK-temperatures, and
+find them independent of temperature and drive power. This suggests that the
+measured frequency noise in YIG is dominated by so far undetermined noise
+sources, which properties are not consistent with the conventional model of
+two-level systems, despite their effect on the sample linewidth. Moreover, the
+functional form of the FMR frequency noise power spectral density (PSD) cannot
+be described by a simple power law. By employing time-series analysis, we find
+a closed function for the PSD that fits our observations. Our results underline
+the necessity of coherence improvements to magnon systems for useful
+applications in quantum magnonics.",2107.06531v1
+2021-08-25,Quantum network with magnonic and mechanical nodes,"A quantum network consisting of magnonic and mechanical nodes connected by
+light is proposed. Recent years have witnessed a significant development in
+cavity magnonics based on collective spin excitations in ferrimagnetic
+crystals, such as yttrium iron garnet (YIG). Magnonic systems are considered to
+be a promising building block for a future quantum network. However, a major
+limitation of the system is that the coherence time of the magnon excitations
+is limited by their intrinsic loss (typically in the order of 1 $\mu$s for
+YIG). Here, we show that by coupling the magnonic system to a mechanical system
+using optical pulses, an arbitrary magnonic state (either classical or quantum)
+can be transferred to and stored in a distant long-lived mechanical resonator.
+The fidelity depends on the pulse parameters and the transmission loss. We
+further show that the magnonic and mechanical nodes can be prepared in a
+macroscopic entangled state. These demonstrate the quantum state transfer and
+entanglement distribution in such a novel quantum network of magnonic and
+mechanical nodes. Our work shows the possibility to connect two separate fields
+of optomagnonics and optomechanics, and to build a long-distance quantum
+network based on magnonic and mechanical systems.",2108.11156v3
+2021-12-20,Spin current transport in hybrid Pt / multifunctional magnetoelectric Ga0.6Fe1.4O3 bilayers,"The low power manipulation of magnetization is currently a highly
+sought-after objective in spintronics. Non ferromagnetic large spin-orbit
+coupling heavy metal (NM) / ferromagnet (FM) heterostructures offer interesting
+elements of response to this issue, by granting the manipulation of the FM
+magnetization by the NM spin Hall effect (SHE) generated spin current.
+Additional functionalities, such as the electric field control of the spin
+current generation, can be offered using multifunctional ferromagnets. We have
+studied the spin current transfer processes between Pt and the multifunctional
+magnetoelectric Ga0.6Fe1.4O3 (GFO). In particular, via angular dependent
+magnetotransport measurements, we were able to differentiate between magnetic
+proximity effect (MPE)-induced anisotropic magnetoresistance (AMR) and spin
+Hall magnetoresistance (SMR). Our analysis shows that SMR is the dominant
+phenomenon at all temperatures and is the only one to be considered near room
+temperature, with a magnitude comparable to those observed in Pd/YIG or Pt/YIG
+heterostructures. These results indicate that magnetoelectric GFO thin films
+show promises for achieving an electric-field control of the spin current
+generation in NM/FM oxide-based heterostructures.",2112.10406v1
+2022-02-06,Enhancing Perpendicular Magnetic Anisotropy in Garnet Ferrimagnet by Interfacing with Few-Layer WTe2,"Engineering magnetic anisotropy in a ferro- or ferrimagnetic (FM) thin film
+is crucial in spintronic device. One way to modify the magnetic anisotropy is
+through the surface of the FM thin film. Here, we report the emergence of a
+perpendicular magnetic anisotropy (PMA) induced by interfacial interactions in
+a heterostructure comprised of a garnet ferrimagnet, Y3Fe5O12 (YIG), and the
+low-symmetry, high spin orbit coupling (SOC) transition metal dichalcogenide,
+WTe2. At the same time, we also observed an enhancement in Gilbert damping in
+the WTe2 covered YIG area. Both the magnitude of interface-induced PMA and the
+Gilbert damping enhancement have no observable WTe2 thickness dependence down
+to single quadruple-layer, indicating that the interfacial interaction plays a
+critical role. The ability of WTe2 to enhance the PMA in FM thin film, combined
+with its previously reported capability to generate out-of-plane damping like
+spin torque, makes it desirable for magnetic memory applications.",2202.02834v1
+2022-02-25,Direct probing of strong magnon-photon coupling in a planar geometry,"We demonstrate direct probing of strong magnon-photon coupling using
+Brillouin light scattering spectroscopy in a planar geometry. The magnonic
+hybrid system comprises a split-ring resonator loaded with epitaxial yttrium
+iron garnet thin films of 200 nm and 2.46 $\mu$m thickness. The Brillouin light
+scattering measurements are combined with microwave spectroscopy measurements
+where both biasing magnetic field and microwave excitation frequency are
+varied. The cooperativity for the 200 nm-thick YIG films is 4.5, and larger
+cooperativity of 137.4 is found for the 2.46 $\mu$m-thick YIG film. We show
+that Brillouin light scattering is advantageous for probing the magnonic
+character of magnon-photon polaritons, while microwave absorption is more
+sensitive to the photonic character of the hybrid excitation. A miniaturized,
+planar device design is imperative for the potential integration of magnonic
+hybrid systems in future coherent information technologies, and our results are
+a first stepping stone in this regard. Furthermore, successfully detecting the
+magnonic hybrid excitation by Brillouin light scattering is an essential step
+for the up-conversion of quantum signals from the optical to the microwave
+regime in hybrid quantum systems.",2202.12696v1
+2022-06-27,Thermal spin current generation in the multifunctional ferrimagnet Ga$_{0.6}$Fe$_{1.4}$O$_{3}$,"In recent years, multifunctional materials have attracted increasing interest
+for magnetic memories and energy harvesting applications. Magnetic insulating
+materials are of special interest for this purpose, since they allow the design
+of more efficient devices due to the lower Joule heat losses. In this context,
+Ga$_{0.6}$Fe$_{1.4}$O$_3$ (GFO) is a good candidate for spintronics
+applications, since it can exhibit multiferroicity and presents a spin Hall
+magnetoresistance similar to the one observed in a yttrium iron garnet (YIG)/Pt
+bilayer. Here, we explore GFO utilizing thermo-spin measurements in an on-chip
+approach. By carefully considering the geometry of our thermo-spin devices we
+are able to quantify the spin Seebeck effect and the spin current generation in
+a GFO/Pt bilayer, obtaining a value comparable to that of YIG/Pt. This further
+confirms the promises of an efficient spin current generation with the
+possibility of an electric-field manipulation of the magnetic properties of the
+system in an insulating ferrimagnetic material.",2206.13426v2
+2022-11-16,Detection sensitivity enhancement of magnon Kerr nonlinearity in cavity magnonics induced by coherent perfect absorption,"We show how to enhance the detection sensitivity of magnon Kerr nonlinearity
+(MKN) in cavity magnonics. The considered cavity-magnon system consists of a
+three-dimensional microwave cavity containing two yttrium iron garnet (YIG)
+spheres, where the two magnon modes (one has the MKN, while the other is
+linear) in YIG spheres are simultaneously coupled to microwave photons. To
+obtain the effective gain of the cavity mode, we feed two input fields into the
+cavity. By choosing appropriate parameters, the coherent perfect absorption of
+the two input fields occurs, and the cavity-magnon system can be described by
+an effective non-Hermitian Hamiltonian. Under the pseudo-Hermitian conditions,
+the effective Hamiltonian can host the third-order exceptional point (EP3),
+where the three eigenvalues of the Hamiltonian coalesce into one. When the
+magnon frequency shift $\Delta_K$ induced by the MKN is much smaller than the
+linewidths $\Gamma$ of the peaks in the transmission spectrum of the cavity
+(i.e., $\Delta_K\ll \Gamma$), the magnon frequency shift can be amplified by
+the EP3, which can be probed via the output spectrum of the cavity. The scheme
+we present provides an alternative approach to measure the MKN in the region
+$\Delta_K\ll \Gamma$ and has potential applications in designing low-power
+nonlinear devices based on the MKN.",2211.08922v2
+2022-12-22,Spin wave dispersion of ultra-low damping hematite ($α\text{-Fe}_2\text{O}_3$) at GHz frequencies,"Low magnetic damping and high group velocity of spin waves (SWs) or magnons
+are two crucial parameters for functional magnonic devices. Magnonics research
+on signal processing and wave-based computation at GHz frequencies focussed on
+the artificial ferrimagnetic garnet Y$_3$Fe$_5$O$_{12}$ (YIG) so far. We report
+on spin-wave spectroscopy studies performed on the natural mineral hematite
+($\alpha\text{-Fe}_2\text{O}_3$) which is a canted antiferromagnet. By means of
+broadband GHz spectroscopy and inelastic light scattering, we determine a
+damping coefficient of $1.1\times10^{-5}$ and magnon group velocities of a few
+10 km/s, respectively, at room temperature. Covering a large regime of wave
+vectors up to $k\approx 24~{\rm rad}/\mu$m, we find the exchange stiffness
+length to be relatively short and only about 1 \r{A}. In a small magnetic field
+of 30 mT, the decay length of SWs is estimated to be 1.1 cm similar to the best
+YIG. Still, inelastic light scattering provides surprisingly broad and partly
+asymmetric resonance peaks. Their characteristic shape is induced by the large
+group velocities, low damping and distribution of incident angles inside the
+laser beam. Our results promote hematite as an alternative and sustainable
+basis for magnonic devices with fast speeds and low losses based on a stable
+natural mineral.",2212.11887v2
+2023-02-02,Ultrastrong Magnon-Photon Coupling Achieved by Magnetic Films in Contact with Superconducting Resonators,"Coherent coupling between spin wave excitations (magnons) and microwave
+photons in a cavity may disclose new paths to unconventional phenomena as well
+as for novel applications. Here, we present a systematic investigation on YIG
+(Yttrium Iron Garnet) films on top of coplanar waveguide resonators made of
+superconducting YBCO. We first show that spin wave excitations with frequency
+higher than the Kittel mode can be excited by putting in direct contact a
+5~$\mu$m thick YIG film with the YBCO coplanar resonator (cavity frequency
+$\omega_c/2 \pi = 8.65$~GHz). With this configuration, we obtain very large
+values of the collective coupling strength $\lambda/2 \pi \approx 2$~GHz and
+cooperativity $C=5 \times 10^4$. Transmission spectra are analyzed by a
+modified Hopfield model for which we provide an exact solution that allows us
+to well reproduce spectra by introducing a limited number of free parameters.
+It turns out that the coupling of the dominant magnon mode with photons exceeds
+0.2 times the cavity frequency, thus demonstrating the achievement of the
+ultrastrong coupling regime with this architecture. Our analysis also shows a
+vanishing contribution of the diamagnetic term which is a peculiarity of pure
+spin systems.",2302.00804v2
+2023-02-10,Laser-induced magnonic band gap formation and control in YIG/GaAs heterostructure,"We demonstrate the laser-induced control over spin-wave (SW) transport in the
+magnonic crystal (MC) waveguide formed from the semiconductor slab placed on
+the ferrite film. We considered bilayer MC with periodical grooves performed on
+the top of the n-type gallium arsenide slab side that oriented to the yttrium
+iron garnet film. To observe the appearance of magnonic gap induced by laser
+radiation, the fabricated structure was studied by the use of microwave
+spectroscopy and Brillouin light-scattering. We perform detailed numerical
+studies of this structure. We showed that the optical control of the magnonic
+gaps (frequency width and position) is related to the variation of the charge
+carriers' concentration in GaAs. We attribute these to nonreciprocity of SW
+transport in the layered structure. Nonreciprocity was induced by the laser
+exposure of the GaAs slab due to SWs' induced electromagnetic field screening
+by the optically-generated charge carriers. We showed that SW dispersion,
+nonreciprocity, and magnonic band gap position and width in the
+ferrite-semiconductor magnonic crystal can be modified in a controlled manner
+by laser radiation. Our results show the possibility of the integration of
+magnonics and semiconductor electronics on the base of YIG/GaAs structures.",2302.05310v1
+2023-11-29,Nonlinear erasing of propagating spin-wave pulses in thin-film Ga:YIG,"Nonlinear phenomena are key for magnon-based information processing, but the
+nonlinear interaction between two spin-wave signals requires their
+spatio-temporal overlap which can be challenging for directional processing
+devices. Our study focuses on a gallium-substituted yttrium iron garnet film,
+which exhibits an exchange-dominated dispersion relation and thus provides a
+particularly broad range of group velocities compared to pure YIG. Using time-
+and space-resolved Brillouin light scattering spectroscopy, we demonstrate the
+excitation of time-separated spin-wave pulses at different frequencies from the
+same source, where the delayed pulse catches up with the previously excited
+pulse and outruns it due to its higher group velocity. By varying the
+excitation power of the faster pulse, the outcome can be finely tuned from a
+linear superposition to a nonlinear interaction of both pulses, resulting in a
+full attenuation of the slower pulse. Therefore, our findings demonstrate the
+all-magnonic erasing process of a propagating magnonic signal, which enables
+the realization of complex temporal logic operations with potential
+application, e.g., in inhibitory neuromorphic functionalities.",2311.17821v2
+2024-01-19,Nonreciprocal Pancharatnam-Berry Metasurface for Unidirectional Wavefront Manipulation,"Optical metasurfaces have been widely used for manipulating electromagnetic
+waves due to their low intrinsic loss and easy fabrication. The metasurfaces
+employing the Pancharatnam-Berry (PB) geometric phase, called PB metasurfaces,
+have been extensively applied to realize spin-dependent functionalities, such
+as beam steering, focusing, holography, etc. The demand for PB metasurfaces in
+complex environments has brought about one challenging problem, i.e., the
+interference of multiple wave channels that limits the performance of PB
+metasurfaces. A promising solution is developing nonreciprocal PB metasurfaces
+that can isolate undesired wave channels and exhibit unidirectional
+functionalities. Here, we propose a mechanism to realize nonreciprocal PB
+metasurfaces of subwavelength thickness by using the magneto-optical effect of
+YIG material in synergy with the PB geometric phase of spatially rotating
+meta-atoms. Using full-wave numerical simulations, we show that the metasurface
+composed of dielectric cylinders and a thin YIG layer can achieve nearly 92%
+and 81% isolation of circularly polarized lights at 5.5 GHz and 6.5 GHz,
+respectively, attributed to the enhancement of the magneto-optical effect by
+the resonant Mie modes and Fabry-P\'erot cavity mode. In addition, the
+metasurface can enable efficient unidirectional wavefront manipulations of
+circularly polarized lights, including nonreciprocal beam steering and
+nonreciprocal beam focusing. The proposed metasurface can find highly useful
+applications in optical communications, optical sensing, and quantum
+information processing.",2401.10772v2
+2017-08-06,Thermally Driven Long Range Magnon Spin Currents in Yttrium Iron Garnet due to Intrinsic Spin Seebeck Effect,"The longitudinal spin Seebeck effect refers to the generation of a spin
+current when heat flows across a normal metal/magnetic insulator interface.
+Until recently, most explanations of the spin Seebeck effect use the
+interfacial temperature difference as the conversion mechanism between heat and
+spin fluxes. However, recent theoretical and experimental works claim that a
+magnon spin current is generated in the bulk of a magnetic insulator even in
+the absence of an interface. This is the so-called intrinsic spin Seebeck
+effect. Here, by utilizing a non-local spin Seebeck geometry, we provide
+additional evidence that the total magnon spin current in the ferrimagnetic
+insulator yttrium iron garnet (YIG) actually contains two distinct terms: one
+proportional to the gradient in the magnon chemical potential (pure magnon spin
+diffusion), and a second proportional to the gradient in magnon temperature
+($\nabla T_m$). We observe two characteristic decay lengths for magnon spin
+currents in YIG with distinct temperature dependences: a temperature
+independent decay length of ~ 10 ${\mu}$m consistent with earlier measurements
+of pure ($\nabla T_m = 0$) magnon spin diffusion, and a longer decay length
+ranging from about 20 ${\mu}$m around 250 K and exceeding 80 ${\mu}$m at 10 K.
+The coupled spin-heat transport processes are modeled using a finite element
+method revealing that the longer range magnon spin current is attributable to
+the intrinsic spin Seebeck effect ($\nabla T_m \neq 0$), whose length scale
+increases at lower temperatures in agreement with our experimental data.",1708.01941v3
+2020-08-29,Exploring a quantum-information-relevant magnonic material: Ultralow damping at low temperature in the organic ferrimagnet V[TCNE]x,"Quantum information science and engineering requires novel low-loss magnetic
+materials for magnon-based quantum-coherent operations. The search for low-loss
+magnetic materials, traditionally driven by applications in microwave
+electronics near room-temperature, has gained additional constraints from the
+need to operate at cryogenic temperatures for many applications in quantum
+information science and technology. Whereas yttrium iron garnet (YIG) has been
+the material of choice for decades, the emergence of molecule-based materials
+with robust magnetism and ultra-low damping has opened new avenues for
+exploration. Specifically, thin-films of vanadium tetracyanoethylene (V[TCNE]x)
+can be patterned into the multiple, connected structures needed for hybrid
+quantum elements and have shown room-temperature Gilbert damping ({\alpha} = 4
+\times 10^-5) that rivals the intrinsic (bulk) damping otherwise seen only in
+highly-polished YIG spheres (far more challenging to integrate into arrays).
+Here, we present a comprehensive and systematic study of the low-temperature
+magnetization dynamics for V[TCNE]x thin films, with implications for their
+application in quantum systems. These studies reveal a temperature-driven,
+strain-dependent magnetic anisotropy that compensates the thin-film shape
+anisotropy, and the recovery of a magnetic resonance linewidth at 5 K that is
+comparable to room-temperature values (roughly 2 G at 9.4 GHz). We can account
+for these variations of the V[TCNE]x linewidth within the context of scattering
+from very dilute paramagnetic impurities, and anticipate additional linewidth
+narrowing as the temperature is further reduced.",2008.13061v3
+2022-10-15,Non-local magnon transconductance in extended magnetic insulating films.\\ Part I: spin diode effect,"This review provides a comprehensive study of the nonlinear transport
+properties of magnons, which are electrically emitted or absorbed inside
+extended YIG films by spin transfer effects via a YIG$\vert$Pt interface. Our
+purpose is to experimentally elucidate the pertinent picture behind the
+asymmetric electrical variation of the magnon transconductance analogous to an
+electric diode. The feature is rooted in the variation of the density of
+low-lying spin excitations via an electrical shift of the magnon chemical
+potential. As the intensity of the spin transfer increases in the forward
+direction (regime of magnon emission), the transport properties of low-energy
+magnon go through 3 distinct regimes: \textit{i)} at low currents, where the
+spin current is a linear function of the electrical current, the spin transport
+is ballistic and set by the film thickness; \textit{ii)} for amplitudes of the
+order of the damping compensation threshold, it switches to a highly correlated
+regime limited by magnon-magnon relaxation process and marked by a saturation
+of the magnon transconductance. Here the main bias, that controls the magnon
+density, are thermal fluctuations beneath the emitter. \textit{iii)} As the
+temperature under the emitter approaches the Curie temperature, scattering with
+high-energy magnons dominates, leading to diffusive transport. We note that
+such sequence of transport regimes bears analogy with electron hydrodynamic
+transport in ultra-pure media predicted by Radii Gurzhi. This study restricted
+to low energy part of the magnon manifold complements part II of this
+review\cite{kohno_2F}, which concentrates instead on the whole spectrum of
+propagating magnons.",2210.08304v2
+1997-10-07,Macroscopic Quantum Tunneling of Ferromagnetic Domain Walls,"Quantum tunneling of domain walls out of an impurity potential in a
+mesoscopic ferromagnetic sample is investigated. Using improved expressions for
+the domain wall mass and for the pinning potential, we find that the cross-over
+temperature between thermal activation and quantum tunneling is of a different
+functional form than found previously. In materials like Ni or YIG, the
+crossover temperatures are around 5 mK. We also find that the WKB exponent is
+typically two orders of magnitude larger than current estimates. The sources
+for these discrepancies are discussed, and precise estimates for the transition
+from three-dimensional to one-dimensional magnetic behavior of a wire are
+given. The cross-over temperatures from thermal to quantum transitions and
+tunneling rates are calculated for various materials and sample sizes.",9710064v1
+2009-06-29,A Magnetization Sensitive Potential at Garnet-Metal Interfaces,"We investigate a magnetization-dependent voltage that appears at the
+interface between garnets and various metals. The voltage is even in the
+applied magnetic field and is dependent on the surface roughness and the
+pressure holding the surfaces together. Large variations in the size, sign and
+magnetic dependence are observed between different metal surfaces. Some
+patterns have been identified in the measured voltages and a simple model is
+described that can accommodate the gross features. The bulk magnetoelectric
+response of one of our polycrystalline YIG samples is measured and is found to
+be consistent with a term in the free energy that is quadratic in both the
+electric and magnetic fields. However, the presence of such a term does not
+fully explain the complex magnetization dependence of the measured voltages.",0906.5340v2
+2010-08-27,Enhancement of the spin pumping efficiency by spin-wave mode selection,"The spin pumping efficiency of lateral standing spin wave modes in a
+rectangular YIG/Pt sample has been investigated by means of the inverse
+spin-Hall effect (ISHE). The standing spin waves drive spin pumping, the
+generation of spin currents from magnetization precession, into the Pt layer
+which is converted into a detectable voltage due to the ISHE. We discovered
+that the spin pumping efficiency is significantly higher for lateral standing
+surface spin waves rather than for volume spin wave modes. The results suggest
+that the use of higher-mode surface spin waves allows for the fabrication of an
+efficient spin-current injector.",1008.4714v2
+2011-12-21,Direct detection of magnon spin transport by the inverse spin Hall effect,"Conversion of traveling magnons into an electron carried spin current is
+demonstrated in a time resolved experiment using a spatially separated
+inductive spin-wave source and an inverse spin Hall effect (ISHE) detector. A
+short spin-wave packet is excited in a yttrium-iron garnet (YIG) waveguide by a
+microwave signal and is detected at a distance of 3 mm by an attached Pt layer
+as a delayed ISHE voltage pulse. The delay in the detection appears due to the
+finite spin-wave group velocity and proves the magnon spin transport. The
+experiment suggests utilization of spin waves for the information transfer over
+macroscopic distances in spintronic devices and circuits.",1112.4969v1
+2013-02-06,Theory of spin Hall magnetoresistance,"We present a theory of the spin Hall magnetoresistance (SMR) in multilayers
+made from an insulating ferromagnet F, such as yttrium iron garnet (YIG), and a
+normal metal N with spin-orbit interactions, such as platinum (Pt). The SMR is
+induced by the simultaneous action of spin Hall and inverse spin Hall effects
+and therefore a non-equilibrium proximity phenomenon. We compute the SMR in
+F$|$N and F$|$N$|$F layered systems, treating N by spin-diffusion theory with
+quantum mechanical boundary conditions at the interfaces in terms of the
+spin-mixing conductance. Our results explain the experimentally observed spin
+Hall magnetoresistance in N$|$F bilayers. For F$|$N$|$F spin valves we predict
+an enhanced SMR amplitude when magnetizations are collinear. The SMR and the
+spin-transfer torques in these trilayers can be controlled by the magnetic
+configuration.",1302.1352v1
+2013-02-27,Specific heat and thermal conductivity of ferromagnetic magnons in Yttrium Iron Garnet,"The specific heat and thermal conductivity of the insulating ferrimagnet
+Y$_3$Fe$_5$O$_{12}$ (Yttrium Iron Garnet, YIG) single crystal were measured
+down to 50 mK. The ferromagnetic magnon specific heat $C$$_m$ shows a
+characteristic $T^{1.5}$ dependence down to 0.77 K. Below 0.77 K, a downward
+deviation is observed, which is attributed to the magnetic dipole-dipole
+interaction with typical magnitude of 10$^{-4}$ eV. The ferromagnetic magnon
+thermal conductivity $\kappa_m$ does not show the characteristic $T^2$
+dependence below 0.8 K. To fit the $\kappa_m$ data, both magnetic defect
+scattering effect and dipole-dipole interaction are taken into account. These
+results complete our understanding of the thermodynamic and thermal transport
+properties of the low-lying ferromagnetic magnons.",1302.6739v1
+2013-05-14,Exchange magnetic field torques in YIG/Pt bilayers observed by the spin-Hall magnetoresistance,"The effective field torque of an yttrium-iron-garnet film on the spin
+accumulation in an attached Pt film is measured by the spin-Hall
+magnetoresistance (SMR). As a result, the magnetization direction of a
+ferromagnetic insulating layer can be measured electrically. Experimental
+transverse and longitudinal resistances are well described by the theoretical
+model of SMR in terms of the direct and inverse spin-Hall effect, for different
+Pt thicknesses [3, 4, 8 and 35nm]. Adopting a spin-Hall angle of Pt
+$\theta_{SH}=0.08$, we obtain the spin diffusion length of Pt
+($\lambda=1.1\pm0.3$nm) as well as the real
+($G_r=(7\pm3)\times10^{14}\Omega^{-1}$m$^{-2}$) and imaginary part
+($G_i=(5\pm3)\times10^{13}\Omega^{-1}$m$^{-2}$) of the spin-mixing conductance
+and their ratio ($G_r/G_i=16\pm4$).",1305.3117v2
+2013-07-29,Current-induced spin wave excitation in Pt|YIG bilayer,"We develop a self-consistent theory for current-induced spin wave excitations
+in normal metal-magnetic insulator bilayer systems, thereby establishing the
+relation between spin wave excitation and the experimentally controlled
+parameters. We fully take into account the complex spin wave spectrum including
+dipolar interactions and surface anisotropy as well as the spin-pumping at the
+interface. Our results focus on the mode-dependent power close to the critical
+currents for spin wave excitation. The major findings are (a) the spin transfer
+torque can excite different spin-wave modes simultaneously; (b) spin pumping
+counterbalances spin-transfer torque and affects the surface modes more than
+the bulk modes; (c) spin pumping inhibits high frequency spin-wave modes,
+thereby redshifting the excitation spectrum. We can get agreement with
+experiments on yttrium iron garnet|platinum bilayers by postulating the
+existence of surface anisotropy modes.",1307.7607v2
+2014-04-14,Sign of inverse spin Hall voltages generated by ferromagnetic resonance and temperature gradients in yttrium iron garnet|platinum bilayers,"We carried out a concerted effort to determine the absolute sign of the
+inverse spin Hall effect voltage generated by spin currents injected into a
+normal metal. We focus on yttrium iron garnet (YIG)|platinum bilayers at room
+temperature, generating spin currents by microwaves and temperature gradients.
+We find consistent results for different samples and measurement setups that
+agree with theory. We suggest a right-hand-rule to define a positive spin Hall
+angle corresponding to with the voltage expected for the simple case of
+scattering of free electrons from repulsive Coulomb charges.",1404.3490v2
+2014-05-16,Damping of Confined Modes in a Ferromagnetic Thin Insulating Film: Angular Momentum Transfer Across a Nanoscale Field-defined Interface,"We observe a dependence of the damping of a confined mode of precessing
+ferromagnetic magnetization on the size of the mode. The micron-scale mode is
+created within an extended, unpatterned YIG film by means of the intense local
+dipolar field of a micromagnetic tip. We find that damping of the confined mode
+scales like the surface-to-volume ratio of the mode, indicating an interfacial
+damping effect (similar to spin pumping) due to the transfer of angular
+momentum from the confined mode to the spin sink of ferromagnetic material in
+the surrounding film. Though unexpected for insulating systems, the measured
+intralayer spin-mixing conductance $g_{\uparrow \downarrow} = 5.3 \times
+10^{19} {\rm m}^{-2}$ demonstrates efficient intralayer angular momentum
+transfer.",1405.4203v2
+2014-05-28,Electronic control of the spin-wave damping in a magnetic insulator,"It is demonstrated that the decay time of spin-wave modes existing in a
+magnetic insulator can be reduced or enhanced by injecting an in-plane dc
+current, $I_\text{dc}$, in an adjacent normal metal with strong spin-orbit
+interaction. The demonstration rests upon the measurement of the ferromagnetic
+resonance linewidth as a function of $I_\text{dc}$ in a 5~$\mu$m diameter
+YIG(20nm){\textbar}Pt(7nm) disk using a magnetic resonance force microscope
+(MRFM). Complete compensation of the damping of the fundamental mode is
+obtained for a current density of $\sim 3 \cdot 10^{11}\text{A.m}^{-2}$, in
+agreement with theoretical predictions. At this critical threshold the MRFM
+detects a small change of static magnetization, a behavior consistent with the
+onset of an auto-oscillation regime.",1405.7415v1
+2014-10-02,Simultaneous detection of the spin-Hall magnetoresistance and the spin-Seebeck effect in Platinum and Tantalum on Yttrium Iron Garnet,"The spin-Seebeck effect (SSE) in platinum (Pt) and tantalum (Ta) on yttrium
+iron garnet (YIG) has been investigated by both externally heating the sample
+(using an on-chip Pt heater on top of the device) as well as by current-induced
+heating. For SSE measurements, external heating is the most common method to
+obtain clear signals. Here we show that also by current-induced heating it is
+possible to directly observe the SSE, separate from the also present spin-Hall
+magnetoresistance (SMR) signal, by using a lock-in detection technique. Using
+this measurement technique, the presence of additional 2nd order signals at low
+applied magnetic fields and high heating currents is revealed. These signals
+are caused by current-induced magnetic fields (Oersted fields) generated by the
+used AC-current, resulting in dynamic SMR signals.",1410.0551v2
+2015-05-07,Formation of Bright Solitons from Wave Packets with Repulsive Nonlinearity,"Formation of bright envelope solitons from wave packets with a repulsive
+nonlinearity was observed for the first time. The experiments used surface
+spin-wave packets in magnetic yttrium iron garnet (YIG) thin film strips. When
+the wave packets are narrow and have low power, they undergo self-broadening
+during the propagation. When the wave packets are relatively wide or their
+power is relatively high, they can experience self-narrowing or even evolve
+into bright solitons. The experimental results were reproduced by numerical
+simulations based on a modified nonlinear Schr\""odinger equation model.",1505.01882v1
+2015-05-26,Observation of pure inverse spin Hall effect in ferromagnetic metals by FM/AFM exchange bias structures,"We report that the spin current generated by spin Seebeck effect (SSE) in
+yttrium iron garnet (YIG) can be detected by a ferromagnetic metal (NiFe). By
+using the FM/AFM exchange bias structure (NiFe/IrMn), inverse spin Hall effect
+(ISHE) and planar Nernst effect (PNE) of NiFe can be unambiguously separated,
+allowing us to observe a pure ISHE signal. After eliminating the in plane
+temperature gradient in NiFe, we can even observe a pure ISHE signal without
+PNE from NiFe itself. It is worth noting that a large spin Hall angle (0.098)
+of NiFe is obtained, which is comparable with Pt. This work provides a kind of
+FM/AFM exchange bias structures to detect the spin current by charge signals,
+and highlights ISHE in ferromagnetic metals can be used in spintronic research
+and applications.",1505.06911v2
+2015-06-17,Magnetic field control of the spin Seebeck effect,"The origin of the suppression of the longitudinal spin Seebeck effect by
+applied magnetic fields is studied. We perform numerical simulations of the
+stochastic Landau-Lifshitz-Gilbert equation of motion for an atomistic spin
+model and calculate the magnon accumulation in linear temperature gradients for
+different strengths of applied magnetic fields and different length scales of
+the temperature gradient. We observe a decrease of the magnon accumulation with
+increasing magnetic field and we reveal that the origin of this effect is a
+field dependent change of the frequency distribution of the propagating
+magnons. With increasing field the magnonic spin currents are reduced due to a
+suppression of parts of the frequency spectrum. By comparison with measurements
+of the magnetic field dependent longitudinal spin Seebeck effect in YIG thin
+films with various thicknesses, we find that our model describes the
+experimental data very well, demonstrating the importance of this effect for
+experimental systems.",1506.05290v1
+2015-06-19,All electrical coherent control of the magnetization in thin Yittrium Iron Garnet film,"We demonstrate coherent control of time domain ferromagnetic resonance by all
+electrical excitation and detection. Using two ultrashort magnetic field steps
+with variable time delay we control the induction decay in yttrium iron garnet
+(YIG). By setting suitable delay times between the two steps the precession of
+the magnetization can either be enhanced or completely stopped. The method
+allows for a determination of the precession frequency within a few precession
+periods and with an accuracy much higher than can be achieved using fast
+fourier transformation. Moreover it holds the promise to massively increase
+precession amplitudes in pulsed inductive microwave magnetometry (PIMM) using
+low amplitude finite pulse trains. Our experiments are supported by
+micromagnetic simulations which nicely confirm the experimental results.",1506.05935v1
+2015-08-20,Superstrong Coupling of a Microwave Cavity to YIG Magnons,"Multiple-post reentrant 3D lumped cavity modes have been realized to design
+the concept of discrete Whispering Gallery and Fabry-Perot-like Modes for
+multimode microwave Quantum Electrodynamics experiments. Using a magnon
+spin-wave resonance of a submillimeter-sized Yttrium-Iron-Garnet sphere at
+milliKelvin temperatures and a four-post cavity, we demonstrate the
+ultra-strong coupling regime between discrete Whispering Gallery Modes and a
+magnon resonance with strength of 1.84 GHz. By increasing the number of posts
+to eight and arranging them in a D$_4$ symmetry pattern, we expand the mode
+structure to that of a discrete Fabry-Perot cavity and modify the Free Spectral
+Range (FSR). We reach the superstrong coupling regime, where spin-photon
+coupling strength is larger than FSR, with coupling strength in the 1.1 to 1.5
+GHz range.",1508.04967v3
+2015-08-25,Non-local magnetoresistance in YIG/Pt nanostructures,"We study the local and non-local magnetoresistance of thin Pt strips
+deposited onto yttrium iron garnet. The local magnetoresistive response,
+inferred from the voltage drop measured along one given Pt strip upon
+current-biasing it, shows the characteristic magnetization orientation
+dependence of the spin Hall magnetoresistance. We simultaneously also record
+the non-local voltage appearing along a second, electrically isolated, Pt
+strip, separated from the current carrying one by a gap of a few 100 nm. The
+corresponding non-local magnetoresistance exhibits the symmetry expected for a
+magnon spin accumulation-driven process, confirming the results recently put
+forward by Cornelissen et al. [1]. Our magnetotransport data, taken at a series
+of different temperatures as a function of magnetic field orientation, rotating
+the externally applied field in three mutually orthogonal planes, show that the
+mechanisms behind the spin Hall and the non-local magnetoresistance are
+qualitatively different. In particular, the non-local magnetoresistance
+vanishes at liquid Helium temperatures, while the spin Hall magnetoresistance
+prevails.",1508.06130v1
+2015-09-14,Spectral characteristics of time resolved magnonic spin Seebeck effect,"Spin Seebeck effect (SSE) holds promise for new spintronic devices with
+low-energy consumption. The underlying physics, essential for a further
+progress, is yet to be fully clarified. This study of the time resolved
+longitudinal SSE in the magnetic insulator yttrium iron garnet (YIG) concludes
+that a substantial contribution to the spin current stems from small
+wave-vector subthermal exchange magnons. Our finding is in line with the recent
+experiment by S. R. Boona and J. P. Heremans, Phys. Rev. B 90, 064421 (2014).
+Technically, the spin-current dynamics is treated based on the
+Landau-Lifshitz-Gilbert (LLG) equation also including magnons back-action on
+thermal bath, while the formation of the time dependent thermal gradient is
+described self-consistently via the heat equation coupled to the magnetization
+dynamics",1509.04018v1
+2015-11-24,Ferromagnetic Resonance of a YIG film in the Low Frequency Regime,"An improved method for characterizing the magnetic anisotropy of films with
+cubic symmetry is described and is applied to an yttrium iron garnet (111)
+film. Analysis of the FMR spectra performed both in-plane and out-of-plane from
+0.7 to 8 GHz yielded the magnetic anisotropy constants as well as the
+saturation magnetization. The field at which FMR is observed turns out to be
+quite sensitive to anisotropy constants (by more than a factor ten) in the low
+frequency (< 2 GHz) regime and when the orientation of the magnetic field is
+nearly normal to the sample plane; the restoring force on the magnetization
+arising from the magnetocrystalline anisotropy fields is then comparable to
+that from the external field, thereby allowing the anisotropy constants to be
+determined with greater accuracy. In this region, unusual dynamical behaviors
+are observed such as multiple resonances and a switching of FMR resonance with
+only a 1 degree change in field orientation at 0.7 GHz.",1511.07892v1
+2015-12-04,Magnetic field dependence of the magnon spin diffusion length in the magnetic insulator yttrium iron garnet,"We investigated the effect of an external magnetic field on the diffusive
+spin transport by magnons in the magnetic insulator yttrium iron garnet (YIG),
+using a non-local magnon transport measurement geometry. We observed a decrease
+in magnon spin diffusion length $\lambda_m$ for increasing field strengths,
+where $\lambda_m$ is reduced from 9.6$\pm1.2$ $\mu$m at 10 mT to 4.2$\pm0.6$
+$\mu$m at 3.5 T at room temperature. In addition, we find that there must be at
+least one additional transport parameter that depends on the external magnetic
+field. Our results do not allow us to unambiguously determine whether this is
+the magnon equilibrium density or the magnon diffusion constant. These results
+are significant for experiments in the more conventional longitudinal spin
+Seebeck geometry, since the magnon spin diffusion length sets the length scale
+for the spin Seebeck effect as well and is relevant for its understanding.",1512.01410v1
+2016-01-21,Spin pumping in strongly coupled magnon-photon systems,"We experimentally investigate magnon-polaritons, arising in ferrimagnetic
+resonance experiments in a microwave cavity with a tuneable quality factor. To
+his end, we simultaneously measure the electrically detected spin pumping
+signal and microwave reflection (the ferrimagnetic resonance signal) of a
+yttrium iron garnet (YIG) / platinum (Pt) bilayer in the microwave cavity. The
+coupling strength of the fundamental magnetic resonance mode and the cavity is
+determined from the microwave reflection data. All features of the magnetic
+resonance spectra predicted by first principle calculations and an input-output
+formalism agree with our experimental observations. By changing the decay rate
+of the cavity at constant magnon-photon coupling rate, we experimentally tune
+in and out of the strong coupling regime and successfully model the
+corresponding change of the spin pumping signal. Furthermore, we observe the
+coupling and spin pumping of several spin wave modes and provide a quantitative
+analysis of their coupling rates to the cavity.",1601.05681v1
+2016-02-04,Investigation of the unidirectional spin heat conveyer effect in a 200nm thin Yttrium Iron Garnet film,"We have investigated the unidirectional spin wave heat conveyer effect in
+sub-micron thick yttrium iron garnet (YIG) films using lock-in thermography
+(LIT). Although the effect is small in thin layers this technique allows us to
+observe asymmetric heat transport by magnons which leads to asymmetric
+temperature profiles differing by several mK on both sides of the exciting
+antenna, respectively. Comparison of Damon-Eshbach and backward volume modes
+shows that the unidirectional heat flow is indeed due to non-reciprocal
+spin-waves. Because of the finite linewidth, small asymmetries can still be
+observed when only the uniform mode of ferromagnetic resonance is excited. The
+latter is of extreme importance for example when measuring the inverse
+spin-Hall effect because the temperature differences can result in
+thermovoltages at the contacts. Because of the non-reciprocity these
+thermovoltages reverse their sign with a reversal of the magnetic field which
+is typically deemed the signature of the inverse spin-Hall voltage.",1602.01662v1
+2016-03-14,Spin Hall Effect Induced Spin Transfer Through an Insulator,"When charge current passes through a normal metal that exhibits spin Hall
+effect, spin accumulates at the edge of the sample in the transverse direction.
+We predict that this spin accumulation, or spin voltage, enables quantum
+tunneling of spin through an insulator or vacuum to reach a ferromagnet without
+transferring charge. In a normal metal/insulator/ferromagnetic insulator
+trilayer (such as Pt/oxide/YIG), the quantum tunneling explains the
+spin-transfer torque and spin pumping that exponentially decay with the
+thickness of the insulator. In a normal metal/insulator/ferromagnetic metal
+trilayer (such as Pt/oxide/Co), the spin transfer in general does not decay
+monotonically with the thickness of the insulator. Combining with the spin Hall
+magnetoresistance, this tunneling mechanism points to the possibility of a new
+type of tunneling spectroscopy that can probe the magnon density of states of a
+ferromagnetic insulator in an all-electrical and noninvasive manner.",1603.04240v2
+2016-05-01,Magnetoelectric fields for microwave chirality discrimination in enantiomeric liquids,"Chirality discrimination is of a fundamental interest in biology, chemistry,
+and metamaterial studies. In optics, near-field plasmon-resonance spectroscopy
+with superchiral probing fields is effectively applicable for analyses of large
+biomolecules with chiral properties. We show possibility for microwave
+near-field chirality discrimination analysis based on magnon-resonance
+spectroscopy. Newly developed capabilities in microwave sensing using
+magnetoelectric (ME) probing fields originated from multiresonance
+magnetic-dipolar-mode (MDM) oscillations in quasi-2D yttrium-iron-garnet (YIG)
+disks, provide a potential for unprecedented measurements of chemical and
+biological objects. We report on microwave near-field chirality discrimination
+for aqueous D- and L-glucose solutions. The shown ME-field sensing is addressed
+to microwave biomedical diagnostics and pathogen detection and to deepening our
+understanding of microwave-biosystem interactions. It can be also important for
+an analysis and design of microwave chiral metamaterials.",1605.00212v1
+2016-05-30,"An integrated approach to doped thin films with strain tunable magnetic anisotropy: Powder synthesis, target preparation and pulsed laser deposition of Bi:YIG","We present a synthesis/processing method for fabricating ferrimagnetic
+insulator (Bi-doped yttrium iron garnet) thin films with tunable magnetic
+anisotropy. Since the desired magnetic properties rely on controllable
+thickness and successful doping, we pay attention to the entire
+synthesis/processing procedure (nanopowder synthesis, nanocrystalline target
+preparation and pulsed laser deposition (PLD)). Atomically flat films were
+deposited by PLD on (111)-orientated yttrium aluminum garnet. We show a
+significant enhancement of perpendicular anisotropy in the films, caused by
+strain-induced anisotropy. In addition, the perpendicular anisotropy is tunable
+by decreasing the film thickness and overwhelms the shape anisotropy at a
+critical thickness of 3.5 nm.",1605.09084v2
+2016-06-10,Indirect Coupling between Two Cavity Photon Systems via Ferromagnetic Resonance,"We experimentally realize indirect coupling between two cavity modes via
+strong coupling with the ferromagnetic resonance in Yttrium Iron Garnet (YIG).
+We find that some indirectly coupled modes of our system can have a higher
+microwave transmission than the individual uncoupled modes. Using a coupled
+harmonic oscillator model, the influence of the oscillation phase difference
+between the two cavity modes on the nature of the indirect coupling is
+revealed. These indirectly coupled microwave modes can be controlled using an
+external magnetic field or by tuning the cavity height. This work has potential
+for use in controllable optical devices and information processing
+technologies.",1606.03469v1
+2016-07-08,Magnon Polarons in the Spin Seebeck Effect,"Sharp structures in magnetic field-dependent spin Seebeck effect (SSE)
+voltages of Pt/Y$_{3}$Fe$_{5}$O$_{12}$ (YIG) at low temperatures are attributed
+to the magnon-phonon interaction. Experimental results are well reproduced by a
+Boltzmann theory that includes the magnetoelastic coupling (MEC). The SSE
+anomalies coincide with magnetic fields tuned to the threshold of
+magnon-polaron formation. The effect gives insight into the relative quality of
+the lattice and magnetization dynamics.",1607.02312v2
+2016-07-12,Effect of Quantum Tunneling on Spin Hall Magnetoresistance,"We present a formalism that simultaneously incorporates the effect of quantum
+tunneling and spin diffusion on spin Hall magnetoresistance observed in normal
+metal/ferromagnetic insulator bilayers (such as Pt/YIG) and normal
+metal/ferromagnetic metal bilayers (such as Pt/Co), in which the angle of
+magnetization influences the magnetoresistance of the normal metal. In the
+normal metal side the spin diffusion is known to affect the landscape of the
+spin accumulation caused by spin Hall effect and subsequently the
+magnetoresistance, while on the ferromagnet side the quantum tunneling effect
+is detrimental to the interface spin current which also affects the spin
+accumulation. The influence of generic material properties such as spin
+diffusion length, layer thickness, interface coupling, and insulating gap can
+be quantified in a unified manner, and experiments that reveal the quantum
+feature of the magnetoresistance are suggested.",1607.03409v1
+2016-07-13,Surface state dominated spin-charge current conversion in topological insulator/ferromagnetic insulator heterostructures,"We report the observation of ferromagnetic resonance-driven spin pumping
+signals at room temperature in three-dimensional topological insulator thin
+films -- Bi2Se3 and (Bi,Sb)2Te3 -- deposited by molecular beam epitaxy on
+yttrium iron garnet thin films. By systematically varying the Bi2Se3 film
+thickness, we show that the spin-charge conversion efficiency, characterized by
+the inverse Rashba-Edelstein effect length (lambda_IREE), increases
+dramatically as the film thickness is increased from 2 quintuple layers,
+saturating above 6 quintuple layers. This suggests a dominant role of surface
+states in spin and charge interconversion in topological insulator/ferromagnet
+heterostructures. Our conclusion is further corroborated by studying a series
+of YIG/(BiSb)2Te3 heterostructures. Finally, we use the ferromagnetic resonance
+linewidth broadening and the inverse Rashba-Edelstein signals to determine the
+effective interfacial spin mixing conductance and lambda_IREE.",1607.03872v1
+2016-08-05,On supercurrents in Bose-Einstein magnon condensates in YIG ferrimagnet,"Recently E. Sonin commented [1] on our preprint ""Supercurrent in a room
+temperature Bose-Einstein magnon condensate"" [2,3], arguing that our ""claim of
+detection of spin supercurrent is premature and has not been sufficiently
+supported by presented experimental results and their theoretical
+interpretation."" We consider the appearance of this Comment as a sign of
+significant interest into the problem of supercurrents in Bose-Einstein magnon
+condensates. Here, we explicitly address E. Sonin's comments and show that our
+interpretation of our experimental results as a detection of a magnon
+supercurrent is fully supported not only by the experimental results
+themselves, but also by independent theoretical analysis [4].",1608.01813v2
+2016-10-31,Strong coupling of magnons in a YIG sphere to photons in a planar superconducting resonator in the quantum limit,"We report measurements of a superconducting coplanar waveguide resonator
+(CPWR) coupled to a sphere of yttrium-iron garnet. The non-uniform CPWR field
+allows us to excite various magnon modes in the sphere. Mode frequencies and
+relative coupling strengths are consistent with theory. Strong coupling is
+observed to several modes even with, on average, less than one excitation
+present in the CPWR. The time response to square pulses shows oscillations at
+the mode splitting frequency. These results indicate the feasibility of
+combining magnonic and planar superconducting quantum devices.",1610.09963v2
+2017-01-03,Magnetic control of Goos-Hanchen shifts in a yttrium-iron-garnet film,"We investigate the Goos-Hanchen (G-H) shifts reflected and transmitted by a
+yttrium-iron-garnet (YIG) film for both normal and oblique incidence. It is
+found that the nonreciprocity effect of the MO material does not only result in
+a nonvanishing reflected shift at normal incidence, but also leads to a
+slab-thickness-independent term which breaks the symmetry between the reflected
+and transmitted shifts at oblique incidence. The asymptotic behaviors of the
+normal-incidence reflected shift are obtained in the vicinity of two
+characteristic frequencies corresponding to a minimum reflectivity and a total
+reflection, respectively. Moreover, the coexistence of two types of
+negative-reflected-shift (NRS) at oblique incidence is discussed. We show that
+the reversal of the shifts from positive to negative values can be realized by
+tuning the magnitude of applied magnetic field, the frequency of incident wave
+and the slab thickness as well as the incident angle. In addition, we further
+investigate two special cases for practical purposes: the reflected shift with
+a total reflection and the transmitted shift with a total transmission.
+Numerical simulations are also performed to verify our analytical results.",1701.01462v2
+2017-02-10,"Relative weight of the inverse spin Hall and spin rectification effects for metallic Py,Fe/Pt and insulating YIG/Pt bilayers estimated by angular dependent spin pumping measurements","We quantify the relative weight of inverse spin Hall and spin rectification
+effects occurring in RF-sputtered polycrystalline permalloy, molecular beam
+epitaxy-grown epitaxial iron and liquid phase epitaxy-grown yttrium-iron-garnet
+bilayer systems with different capping materials. To distinguish the spin
+rectification signal from the inverse spin Hall voltage the external magnetic
+field is rotated in-plane to take advantage of the different angular
+dependencies of the prevailing effects. We prove that in permalloy anisotropic
+magnetoresistance is the dominant source for spin rectification while in
+epitaxial iron the anomalous Hall effect has an also comparable strength. The
+rectification in yttrium-iron-garnet/platinum bilayers reveals an angular
+dependence imitating the one seen for anisotropic magnetoresistance caused by
+spin Hall magnetoresistance.",1702.03119v1
+2017-02-20,Parametric pumping of spin waves by acoustic waves,"The linear and nonlinear interactions between spin waves (magnons) and
+acoustic waves (phonons) in magnetostrictive materials provide an exciting
+opportunity for realizing novel microwave signal processing devices and
+spintronic circuits. Here we demonstrate the parametric pumping of spin waves
+by acoustic waves, the possibility of which has long been theoretically
+anticipated but never experimentally realized. Spin waves propagating in a thin
+film of yttrium iron garnet (YIG), a magnetostrictive ferrimagnet with low spin
+and acoustic wave damping, are pumped using an acoustic resonator driven at
+frequencies near twice the spin wave frequency. The observation of a
+counter-propagating idler wave and a distinct pump threshold that increases
+quadratically with frequency non-degeneracy are evidence of a nonlinear
+parametric pumping process consistent with classical theory. This demonstration
+of acoustic parametric pumping lays the groundwork for developing new
+spintronic and microwave signal processing devices based on amplification and
+manipulation of spin waves by efficient, spatially localized acoustic
+transducers.",1702.06038v1
+2017-03-22,Fabrication and magnetic control of Y3Fe5O12 cantilevers,"We have fabricated ferrite cantilevers in which their vibrational properties
+can be controlled by external magnetic fields. Submicron-scale cantilever
+structures were made from Y3Fe5O12 (YIG) films by physical etching combined
+with use of a focused ion beam milling technique. We found that the cantilevers
+exhibit two resonance modes which correspond to horizontal and vertical
+vibrations. Under external magnetic fields, the resonance frequency of the
+horizontal mode increases, while that of the vertical mode decreases,
+quantitatively consistent with our numerical simulation for magnetic forces.
+The changes in resonance frequencies with magnetic fields reach a few percent,
+showing that efficient magnetic control of resonance frequencies was achieved.",1703.07533v1
+2017-05-05,Nano-patterned magnonic crystals based on ultrathin YIG films,"We demonstrate a microscopic magnonic-crystal waveguide produced by
+nano-patterning of a 20 nm thick film of Yttrium Iron Garnet. By using the
+phase-resolved micro-focus Brillouin light scattering spectroscopy, we map the
+intensity and the phase of spin waves propagating in such a periodic magnetic
+structure. Based on these maps, we obtain the dispersion and the attenuation
+characteristics of spin waves providing detailed information about the physics
+of spin-wave propagation in the magnonic crystal. We show that, in contrast to
+the simplified physical picture, the maximum attenuation of spin waves is
+achieved close to the edge of the magnonic band gap, which is associated with
+non-trivial reflection characteristics of spin waves in non-uniform field
+potentials.",1705.02267v1
+2017-05-06,Scaling of the spin Seebeck effect in bulk and thin film,"Whilst there have been several reports of the spin Seebeck effect to date,
+comparison of the absolute voltage(s) measured, in particular for thin films,
+is limited. In this letter we demonstrate normalization of the spin Seebeck
+effect for Fe$_3$O$_4$:Pt thin film and YIG:Pt bulk samples with respect to the
+heat flux J$_q$, and temperature difference $\Delta$T. We demonstrate that the
+standard normalization procedures for these measurements do not account for an
+unexpected scaling of the measured voltage with area that is observed in both
+bulk and thin film. Finally, we present an alternative spin Seebeck coefficient
+for substrate and sample geometry independent characterization of the spin
+Seebeck effect.",1705.02491v3
+2017-05-09,"Anomalous, spin, and valley Hall effects in graphene deposited on ferromagnetic substrates","Spin, anomalous, and valley Hall effects in graphene-based hybrid structures
+are studied theoretically within the Green function formalism and linear
+response theory. Two different types of hybrid systems are considered in
+detail: (i) graphene/boron nitride/cobalt(nickel), and (ii) graphene/YIG. The
+main interest is focused on the proximity-induced exchange interaction between
+graphene and magnetic substrate and on the proximity-enhanced spin-orbit
+coupling. The proximity effects are shown to have a significant influence on
+the electronic and spin transport properties of graphene. To find the spin,
+anomalous and valley Hall conductivities we employ certain effective
+Hamiltonians which have been proposed recently for the hybrid systems under
+considerations. Both anomalous and valley Hall conductivities have universal
+values when the Fermi level is inside the energy gap in the electronic
+spectrum.",1705.03220v1
+2017-06-06,Spin Seebeck effect and magnon-magnon drag in Pt/YIG/Pt structures,"The formation of the two: injected (""coherent"") and ""thermally"" excited,
+different in energies magnon subsystems and the influence of its interaction
+with phonons and between on drag effect under spin Seebeck effect conditions in
+the magnetic insulator part of the metal/ferromagnetic insulator/metal
+structure is studied. An approximation of the effective parameters, when each
+of the interacting subsystems (""injected"", ""thermal"" magnons, and phonons) is
+characterized by its own effective temperature and drift velocities have been
+considered. The analysis of the macroscopic momentum balance equations of the
+systems of interest conducted for different ratios of the drift velocities of
+the magnon and phonon currents show that the ""injected"" magnons relaxation on
+the ""thermal"" ones is possible to be dominant over its relaxation on phonons.
+This interaction will be the defining in the forming of the temperature
+dependence of the spin-wave current under spin Seebeck effect conditions, and
+inelastic part of the magnon-magnon interaction is the dominant spin relaxation
+mechanism.",1706.02154v1
+2017-10-16,Positive-Negative Birefringence in Multiferroic Layered Metasurfaces,"We uncover and identify the regime for a magnetically and ferroelectrically
+controllable negative refraction of light traversing multiferroic, oxide-based
+metastructure consisting of alternating nanoscopic ferroelectric (SrTiO$_2$)
+and ferromagnetic (Y$_3$Fe$_2$(FeO$_4$)$_3$, YIG) layers. We perform analytical
+and numerical simulations based on discretized, coupled equations for the
+self-consistent Maxwell/ferroelectric/ferromagnetic dynamics and obtain a
+biquadratic relation for the refractive index. Various scenarios of ordinary
+and negative refraction in different frequency ranges are analyzed and
+quantified by simple analytical formula that are confirmed by full-fledge
+numerical simulations. Electromagnetic-waves injected at the edges of the
+sample are propagated exactly numerically. We discovered that for particular
+GHz frequencies, waves with different polarizations are characterized by
+different signs of the refractive index giving rise to novel types of phenomena
+such as a positive-negative birefringence effect, and magnetically controlled
+light trapping and accelerations.",1710.05995v1
+2017-10-18,Strong Coupling of 3D Cavity Photons to Travelling Magnons At Low Temperatures,"We demonstrate strong coupling between travelling magnons in an Yttrium Iron
+Garnet film and 3D microwave cavity photons at milli-Kelvin temperatures. The
+coupling strength of $350$MHz or $7.3$\% of resonance frequency is observed.
+The magnonic subsystem is represented by the Damon-Eshbach magnetostatic
+surface wave with a distribution of wave numbers giving the linewidth of 15MHz.
+The ways to improve this parameter are discussed. The energy gap in the
+spectrum given by the Zeeman energy and the shape-anisotropy energy in the film
+geometry give rise to a significant asymmetry of the double peak structure of
+the photon-magnon avoided level crossing. A structure of two parallel YIG films
+is investigated using the same re-entrant magnetostatic surface wave transducer
+revealing a higher order magnon modes existing in both films. Combination of a
+multi-post re-entrant cavity and multiple films is a potential base for
+engineering both magnon and photon spectra.",1710.06601v1
+2017-11-01,Spin current noise of the spin Seebeck effect and spin pumping,"We theoretically investigate the fluctuation of a pure spin current induced
+by the spin Seebeck effect and spin pumping in a normal metal (NM)/ferromagnet
+(FM) bilayer system. Starting with a simple FI--NM interface model with both
+spin-conserving and spin-non-conserving processes, we derive general
+expressions of the spin current and the spin-current noise at the interface
+within second-order perturbation of the FI--NM coupling strength, and estimate
+them for an yttrium iron garnet (YIG) --platinum interface. We show that the
+spin-current noise can be used to determine the effective spin carried by a
+magnon, modified by the spin-non-conserving process at the interface. In
+addition, we show that it provides information on the effective spin of a
+magnon, heating at the interface under spin pumping, and spin Hall angle of the
+NM.",1711.00237v2
+2017-12-11,Predicting the Spin Seebeck Voltage in Spin-polarized Materials: A Quantum Mechanical Transport Model Approach,"The spin Seebeck effect has recently been demonstrated as a viable method of
+direct energy conversion that has potential to outperform energy conversion
+from the conventional Seebeck effect. In this study, a computational transport
+model is developed and validated that predicts the spin Seebeck voltage in
+spin-polarized materials using material parameter obtain from first principle
+ground state density functional calculations. The transport model developed is
+based on a 1D effective mass description coupled with a microscopic inverse
+spin Hall relationship. The model can predict both the spin current and voltage
+generated in a non-magnetic material placed on top of a ferromagnetic material
+in a transverse spin Seebeck configuration. The model is validated and verified
+with available experimental data of La:YIG. Future applications of this model
+include the high-throughput exploration of new spin-based thermoelectric
+materials.",1712.04074v1
+2018-01-09,Negative spin Hall magnetoresistance in antiferromagnetic Cr2O3/Ta bilayer at low temperature region,"We investigate the observation of negative spin Hall magnetoresistance (SMR)
+in antiferromagnetic Cr2O3/Ta bilayers at low temperature. The sign of the SMR
+signals is changed from positive to negative monotonously from 300 K to 50 K.
+The change of the signs for SMR is related with the competitions between the
+surface ferromagnetism and bulky antiferromagnetic of Cr2O3. The surface
+magnetizations of Cr2O3 (0001) is considered to be dominated at higher
+temperature, while the bulky antiferromagnetics gets to be robust with
+decreasing of temperature. The slopes of the abnormal Hall curves coincide with
+the signs of SMR, confirming variational interface magnetism of Cr2O3 at
+different temperature. From the observed SMR ratio under 3 T, the spin mixing
+conductance at Cr2O3/Ta interface is estimated to be 1.12*10^14 (ohm^-1*m^-2),
+which is comparable to that of YIG/Pt structures and our early results of
+Cr2O3/W. (Appl. Phys. Lett. 110, 262401 (2017))",1801.02747v1
+2018-04-08,Optical cooling of magnons,"Inelastic scattering of light by spin waves generates an energy flow between
+the light and magnetization fields, a process that can be enhanced and
+controlled by concentrating the light in magneto-optical resonators. Here, we
+model the cooling of a sphere made of a magnetic insulator, such as yttrium
+iron garnet (YIG), using a monochromatic laser source. When the magnon
+lifetimes are much larger than the optical ones, we can treat the latter as a
+Markovian bath for magnons. The steady-state magnons are canonically
+distributed with a temperature that is controlled by the light intensity. We
+predict that such a cooling process can significantly reduce the temperature of
+the magnetic order within current technology.",1804.02683v1
+2018-04-10,Microwave cavity tuned with liquid metal and its application to Electron Paramagnetic Resonance,"This note presents a method to tune the resonant frequency $f_{0}$ of a
+rectangular microwave cavity. This is achieved using a liquid metal, GaInSn, to
+decrease the volume of the cavity. It is possible to shift $f_{0}$ by filling
+the cavity with this alloy, in order to reduce the relative distance between
+the internal walls. The resulting modes have resonant frequencies in the range
+$7\div8\,$GHz. The capability of the system of producing an Electron
+Paramagnetic Resonance (EPR) measurement has been tested by placing a 1 mm
+diameter Yttrium Iron Garnet (YIG) sphere inside the cavity, and producing a
+strong coupling between the cavity resonance and Kittel mode. This work shows
+the possibility to tune a resonant system in the GHz range, which can be useful
+for several applications.",1804.03443v1
+2018-07-03,Spin pinning and spin-wave dispersion in nanoscopic ferromagnetic waveguides,"Spin waves are investigated in Yttrium Iron Garnet (YIG) waveguides with a
+thickness of 39 nm and widths ranging down to 50 nm, i.e., with aspect ratios
+thickness over width approaching unity, using Brillouin Light Scattering
+spectroscopy. The experimental results are verified by a semi-analytical theory
+and micromagnetic simulations. A critical width is found, below which the
+exchange interaction suppresses the dipolar pinning phenomenon. This changes
+the quantization criterion for the spin-wave eigenmodes and results in a
+pronounced modification of the spin-wave characteristics. The presented
+semi-analytical theory allows for the calculation of spin-wave mode profiles
+and dispersion relations in nano-structures.",1807.01358v3
+2018-07-17,Magnon-phonon conversion experiment and phonon spin,"Recent experiment demonstrates magnon to phonon conversion in a YIG film
+under the application of a non-uniform magnetic field. Light scattered from
+phonons is observed to change its polarization state interpreted by the authors
+signifying phonon spin. In this note we argue that the experimental data merely
+shows the exchange of angular momentum $\pm \hbar$ per photon. We suggest that
+it has physical origin in the orbital angular momentum of phonons. The
+distinction between spin and orbital parts of the total angular momentum, and
+between phonons and photons with added emphasis on their polarizations is
+explained. The main conclusion of the present note is that phonon spin
+hypothesis is unphysical.",1807.08614v2
+2018-07-31,Fresnel diffraction of spin waves,"The propagation of magnetostatic forward volume waves excited by a
+constricted coplanar waveguide is studied via inductive spectroscopy
+techniques. A series of devices consisting of pairs of sub-micrometer size
+antennae is used to perform a discrete mapping of the spin wave amplitude in
+the plane of a 30-nm thin YIG film. We found that the spin wave propagation
+remains well focused in a beam shape of width comparable to the constriction
+length and that the amplitude within the constriction displays oscillations,
+two features which are explained in terms of near-field Fresnel diffraction
+theory.",1807.11754v1
+2018-08-23,First harmonic measurements of the spin Seebeck effect,"We present measurements of the spin Seebeck effect (SSE) by a technique that
+combines alternating currents (AC) and direct currents (DC). The method is
+applied to a ferrimagnetic insulator/heavy metal bilayer,
+Y$_3$Fe$_5$O$_{12}$(YIG)/Pt. Typically, SSE measurements use an AC current to
+produce an alternating temperature gradient and measure the voltage generated
+by the inverse spin-Hall effect in the heavy metal at twice the AC frequency.
+Here we show that when Joule heating is associated with AC and DC bias
+currents, the SSE response occurs at the frequency of the AC current drive and
+can be larger than the second harmonic SSE response. We compare the first and
+second harmonic responses and show that they are consistent with the SSE. The
+field dependence of the voltage response is used to characterize the
+damping-like and field-like torques. This method can be used to explore
+nonlinear thermoelectric effects and spin dynamics induced by temperature
+gradients.",1808.07813v1
+2018-11-29,Efficient spin transport in a paramagnetic insulator,"The discovery of new materials that efficiently transmit spin currents has
+been important for spintronics and material science. The electric insulator
+$\mathrm{Gd}_3\mathrm{Ga}_5\mathrm{O}_{12}$ (GGG) is a superior substrate for
+growing magnetic films, but has never been considered as a conduit for spin
+currents. Here we report spin current propagation in paramagnetic GGG over
+several microns. Surprisingly, the spin transport persists up to temperatures
+of 100 K $\gg$ $T_{\mathrm{g}} = 180$ mK, GGG's magnetic glass-like transition
+temperature. At 5 K we find a spin diffusion length ${\lambda_{\mathrm{GGG}}} =
+1.8 \pm 0.2 {\mu}$m and a spin conductivity ${\sigma}_{\mathrm{GGG}} = (7.3 \pm
+0.3) \times10^4$ $\mathrm{Sm}^{-1}$ that is larger than that of the record
+quality magnet $\mathrm{Y}_3\mathrm{Fe}_5\mathrm{O}_{12}$ (YIG). We conclude
+that exchange coupling is not required for efficient spin transport, which
+challenges conventional models and provides new material-design strategies for
+spintronic devices.",1811.11972v1
+2019-01-04,How to accurately determine a saturation magnetization of the sample in a ferromagnetic resonance experiment?,"The phenomenon of ferromagnetic resonance (FMR) is still being exploited for
+determining the magnetocrystalline anisotropy constants of magnetic materials.
+We show that one can also determine accurately the saturation magnetization of
+the sample using results of FMR experiments after taking into account the
+relationship between resonance frequency and curvature of the spatial
+distribution of free energy at resonance. Specifically, three examples are
+given of calculating saturation magnetization from FMR data: we use historical
+Bickford's measurements from 1950 for bulk magnetite, Liu's measurements from
+2007 for a 500 mn thin film of a weak ferromagnet (Ga, Mn)As, and Wang's
+measurements from 2014 for an ultrathin film of YIG. In all three cases, the
+magnetization values we have determined are consistent with the results of
+measurements.",1901.01207v1
+2019-04-08,Quantum entanglement between two magnon modes via Kerr nonlinearity,"We propose a scheme to entangle two magnon modes via Kerr nonlinear effect
+when driving the systems far-from-equilibrium. We consider two macroscopic
+yttrium iron garnets (YIGs) interacting with a single-mode microcavity through
+the magnetic dipole coupling. The Kittel mode describing the collective
+excitations of large number of spins are excited through driving cavity with a
+strong microwave field. We demonstrate how the Kerr nonlineraity creates the
+entangled quantum states between the two macroscopic ferromagnetic samples,
+when the microcavity is strongly driven by a blue-detuned microwave field. Such
+quantum entanglement survives at the steady state. Our work offers new insights
+and guidance to designate the experiments for observing the entanglement in
+massive ferromagnetic materials. It can also find broad applications in
+macroscopic quantum effects and magnetic spintronics.",1904.04167v1
+2019-08-09,Observation of anti-PT symmetry phase transition in the magnon-cavity-magnon coupled system,"As the counterpart of PT symmetry, abundant phenomena and potential
+applications of anti-PT symmetry have been predicted or demonstrated
+theoretically. However, experimental realization of the coupling required in
+the anti-PT symmetry is difficult. Here, by coupling two YIG spheres to a
+microwave cavity, the large cavity dissipation rate makes the magnons coupled
+dissipatively with each other, thereby obeying a two-dimensional anti-PT
+Hamiltonian. In terms of the magnon-readout method, a new method adopted here,
+we demonstrate the validity of our method in constructing an anti-PT system and
+present the counterintuitive level attraction process. Our work provides a new
+platform to explore the anti-PT symmetry properties and paves the way to study
+multi-magnoncavity-polariton systems.",1908.03358v1
+2019-10-11,Simulation of sympathetic cooling an optically levitated magnetic nanoparticle via coupling to a cold atomic gas,"A proposal for cooling the translational motion of optically levitated
+magnetic nanoparticles is presented. The theoretical cooling scheme involves
+the sympathetic cooling of a ferromagnetic YIG nanosphere with a spin-polarized
+atomic gas. Particle-atom cloud coupling is mediated through the magnetic
+dipole-dipole interaction. When the particle and atom oscillations are small
+compared to their separation, the interaction potential becomes dominantly
+linear which allows the particle to exchange energy with the $N$ atoms. While
+the atoms are continuously Doppler cooled, energy is able to be removed from
+the nanoparticle's motion as it exchanges energy with the atoms. The rate at
+which energy is removed from the nanoparticle's motion was studied for three
+species of atoms (Dy, Cr, Rb) by simulating the full $N+1$ equations of motion
+and was found to depend on system parameters with scalings that are consistent
+with a simplified model. The nanoparticle's damping rate due to sympathetic
+cooling is competitive with and has the potential to exceed commonly employed
+cooling methods.",1910.05371v3
+2019-10-30,Strong coupling-enabled broadband non-reciprocity,"Non-reciprocity of signal transmission enhances capacity of communication
+channels and protects transmission quality against possible signal
+instabilities, thus becoming an important component ensuring coherent
+information processing. However, non-reciprocal transmission requires breaking
+time-reversal symmetry (TRS) which poses challenges of both practical and
+fundamental character hindering the progress. Here we report a new scheme for
+achieving broadband non-reciprocity using a specially engineered hybrid
+microwave cavity. The TRS breaking is realized via strong coherent coupling
+between a selected chiral mode in the microwave cavity and a single collective
+spin excitation (magnon) in a ferromagnetic yttrium iron garnet (YIG) sphere.
+The non-reciprocity in transmission is observed spanning nearly a 0.5 GHz
+frequency band, which outperforms by two orders of magnitude the previously
+achieved bandwidths. Our findings open new directions for robust coherent
+information processing in a broad range of systems in both classical and
+quantum regimes.",1910.14117v2
+2019-11-09,The magnonic superfluid droplet at room temperature,"We declare the observation of spin superfluid state in Yttrium Iron Garnet
+(YIG) at room temperature. It is similar to a Homogeneous Precessing State
+(HPD), observed earlier in antiferromagnetic superfluid $^3$He-B. The formation
+of this state explains by the repulsive interaction between magnons, which is
+required as a prior condition for the spin superfluidity. It establishes an
+energy gap, which stabilizes the long range superfluid transport of
+magnetization and determines the Ginzburg-Landau coherence length. This
+discovery paves a way to many quantum applications of supermagnonics at room
+temperature, such as magnetic Josephson effect, long distance spin transport,
+Q-bit, quantum logics, magnetic sensors and others.",1911.03708v1
+2019-11-26,Ultrastrong coupling between a microwave resonator and antiferromagnetic resonances of rare earth ion spins,"Quantum magnonics is a new and active research field, leveraging the strong
+collective coupling between microwaves and magnetically ordered spin systems.
+To date work in quantum magnonics has focused on transition metals and almost
+entirely on ferromagnetic resonances in yttrium iron garnet (YIG).
+Antiferromagnetic systems have gained interest as they produce no stray field,
+and are therefore robust to magnetic perturbations and have narrow, shape
+independent resonant linewidths. Here we show the first experimental evidence
+of ultrastrong-coupling between a microwave cavity and collective
+antiferromagnetic resonances (magnons) in a rare earth crystal. The combination
+of the unique optical and spin properties of the rare earths and collective
+antiferromagnetic order paves the way for novel quantum magnonic applications.",1911.11311v1
+2019-12-05,Enhanced spin-orbit coupling in a heavy metal via molecular coupling,"Heavy metals are key to spintronics because of their high spin-orbit coupling
+(SOC) leading to efficient spin conversion and strong magnetic interactions.
+When C60 is deposited on Pt, the molecular interface is metallised and the spin
+Hall angle in YIG/Pt increased, leading to an enhancement of up to 600% in the
+spin Hall magnetoresistance and 700% for the anisotropic magnetoresistance.
+This correlates with Density Functional Theory simulations showing changes of
+0.46 eV/C60 in the SOC of Pt. This effect opens the possibility of gating the
+molecular hybridisation and SOC of metals.",1912.02712v2
+2020-02-11,Sub-micrometer near-field focusing of spin waves in ultrathin YIG films,"We experimentally demonstrate tight focusing of a spin wave beam excited in
+extended nanometer-thick films of Yttrium Iron Garnet by a simple microscopic
+antenna functioning as a single-slit near-field lens. We show that the focal
+distance and the minimum transverse width of the focal spot can be controlled
+in a broad range by varying the frequency/wavelength of spin waves and the
+antenna geometry. The experimental data are in good agreement with the results
+of numerical simulations. Our findings provide a simple solution for
+implementation of magnonic nano-devices requiring local concentration of the
+spin-wave energy.",2002.04284v1
+2020-03-27,Electrical detection of unconventional transverse spin-currents in obliquely magnetized thin films,"In a typical experiment in magnonics, thin films are magnetized in-plane and
+spin waves only carry angular momentum along their spatial propagation
+direction. Motivated by the experiments of Bozhko et al. [Phys. Rev. Research
+2, 023324 (2020)], we show theoretically that for obliquely magnetized thin
+films, exchange-dipolar spin waves are accompanied by a transverse
+spin-current. We propose an experiment to electrically detect this transverse
+spin-current with Pt strips on top of a YIG film, by comparing the induced
+spin-current for spin waves with opposite momenta. We predict the relative
+difference to be of the order $10^{-4}$, for magnetic fields tilted at least
+$30^{\circ}$ out of plane. This transverse spin-current is the result of the
+long range dipole-dipole interaction and the inversion symmetry breaking of the
+interface.",2003.12520v4
+2020-03-12,"Tunable multiwindow magnomechanically induced transparency, Fano resonances, and slow-to-fast light conversion","We investigate the absorption and transmission properties of a weak probe
+field under the influence of a strong control field in a hybrid cavity
+magnomechanical system in the microwave regime. This hybrid system consists of
+two ferromagnetic material yttrium iron garnet (YIG) spheres strongly coupled
+to a single cavity mode. In addition to two magnon-induced transparency (MIT)
+that arise due to strong photon-magnon interactions, we observe a
+magnomechanically induced transparency (MMIT) due to the presence of nonlinear
+phonon-magnon interaction. In addition, we discuss the emergence and tunability
+of the multiple Fano resonances in our system. We find that due to strong
+photon-magnon coupling the group delay of the probe field can be enhanced
+significantly. The subluminal or superluminal propagation depends on the
+frequency of the magnons, which can be easily tuned by an external bias
+magnetic field. Besides, the group delay of the transmitted field can also be
+controlled with the control field power.",2003.13760v4
+2020-05-13,Waveguide cavity optomagnonics for broadband multimode microwave-to-optics conversion,"Cavity optomagnonics has emerged as a promising platform for studying
+coherent photon-spin interactions as well as tunable microwave-to-optical
+conversion. However, current implementation of cavity optomagnonics in
+ferrimagnetic crystals remains orders of magnitude larger in volume than
+state-of-the-art cavity optomechanical devices, resulting in very limited
+magneto-optical interaction strength. Here, we demonstrate a cavity
+optomagnonic device based on integrated waveguides and its application for
+microwave-to-optical conversion. By designing a ferrimagnetic rib waveguide to
+support multiple magnon modes with maximal mode overlap to the optical field,
+we realize a high magneto-optical cooperativity which is three orders of
+magnitude higher compared to previous records obtained on polished YIG spheres.
+Furthermore, we achieve tunable conversion of microwave photons at around 8.45
+GHz to 1550 nm light with a broad conversion bandwidth as large as 16.1 MHz.
+The unique features of the system point to novel applications at the crossroad
+between quantum optics and magnonics.",2005.06429v1
+2020-05-18,Local spin Seebeck imaging with scanning thermal probe,"In this work we present the results of an experiment to locally resolve the
+spin Seebeck effect in a high-quality Pt/YIG sample. We achieve this by
+employing a locally heated scanning thermal probe to generate a highly local
+non-equilibrium spin current. To support our experimental results, we also
+present a model based on the non-equilibrium thermodynamic approach which is in
+a good agreement with experimental findings. To further corroborate our
+results, we index the locally resolved spin Seebeck effect with that of the
+local magnetisation texture by MFM and correlate corresponding regions. We
+hypothesise that this technique allows imaging of magnetisation textures within
+the magnon diffusion length and hence characterisation of spin caloritronic
+materials at the nanoscale.",2005.08539v1
+2020-05-20,Frequency mixing in a ferrimagnetic sphere resonator,"Frequency mixing in ferrimagnetic resonators based on yttrium and calcium
+vanadium iron garnets (YIG and CVBIG) is employed for studying their nonlinear
+interactions. The ferrimagnetic Kittel mode is driven by applying a pump tone
+at a frequency close to resonance. We explore two nonlinear frequency mixing
+configurations. In the first one, mixing between a transverse pump tone and an
+added longitudinal weak signal is explored, and the experimental results are
+compared with the predictions of the Landau-Zener-Stuckelberg model. In the
+second one, intermodulation measurements are employed by mixing pump and signal
+tones both in the transverse direction for studying a bifurcation between a
+stable spiral and a stable node attractors. Our results are applicable for
+developing sensitive signal receivers with high gain for both the radio
+frequency and the microwave bands.",2005.09864v1
+2020-06-25,Magnon-exciton proximity coupling at a van der Waals heterointerface,"Spin and photonic systems are at the heart of modern information devices and
+emerging quantum technologies. An interplay between electron-hole pairs
+(excitons) in semiconductors and collective spin excitations (magnons) in
+magnetic crystals would bridge these heterogeneous systems, leveraging their
+individual assets in novel interconnected devices. Here, we report the
+magnon-exciton coupling at the interface between a magnetic thin film and an
+atomically-thin semiconductor. Our approach allies the long-lived magnons
+hosted in a film of yttrium iron garnet (YIG) to strongly-bound excitons in a
+flake of a transition metal dichalcogenide, MoSe$_2$. The magnons induce on the
+excitons a dynamical valley Zeeman effect ruled by interfacial exchange
+interactions. This nascent class of hybrid system suggests new opportunities
+for information transduction between microwave and optical regions.",2006.14257v2
+2020-08-04,Quantitative comparison of magnon transport experiments in three-terminal YIG/Pt nanostructures acquired via dc and ac detection techniques,"All-electrical generation and detection of pure spin currents is a promising
+way towards controlling the diffusive magnon transport in magnetically ordered
+insulators. We quantitatively compare two measurement schemes, which allow to
+measure the magnon spin transport in a three-terminal device based on a yttrium
+iron garnet thin film. We demonstrate that the dc charge current method based
+on the current reversal technique and the ac charge current method utilizing
+first and second harmonic lock-in detection can both efficiently distinguish
+between electrically and thermally injected magnons. In addition, both
+measurement schemes allow to investigate the modulation of magnon transport
+induced by an additional dc charge current applied to the center modulator
+strip. However, while at low modulator charge current both schemes yield
+identical results, we find clear differences above a certain threshold current.
+This difference originates from nonlinear effects of the modulator current on
+the magnon conductance.",2008.01416v1
+2020-09-09,Sub-pico-liter magneto-optical cavities,"Microwave-to-optical conversion via ferromagnetic magnons has so-far been
+limited by the optical coupling rates achieved in mm-scale whispering gallery
+mode resonators. Towards overcoming this limitation, we propose and demonstrate
+an open magneto-optical cavity containing a thin-film of yttrium iron garnet
+(YIG). We achieve a 0.1 pL (100 $\mu$m$^{3}$) optical mode volume, $\sim$50
+times smaller than previous devices. From this, we estimate the magnon
+single-photon coupling rate is $G\approx50$ Hz. This open cavity design offers
+the prospect of wavelength scale mode volumes, small polarization splittings,
+and good magneto-optical mode overlap. With achievable further improvements and
+optimization, efficient microwave-optical conversion and magnon cooling devices
+become a realistic possibility.",2009.04162v1
+2020-10-24,Enhanced sensing of weak anharmonicities through coherences in dissipatively coupled anti-PT symmetric systems,"In the last few years, the great utility of PT-symmetric systems in sensing
+small perturbations has been recognized. Here, we propose an alternate method
+relevant to dissipative systems, especially those coupled to the vacuum of the
+electromagnetic fields. In such systems, which typically show anti-PT symmetry
+and do not require the incorporation of gain, vacuum induces coherence between
+two modes. Owing to this coherence, the linear response acquires a pole on the
+real axis. We demonstrate how this coherence can be exploited for the enhanced
+sensing of very weak anhamonicities at low pumping rates. Higher drive powers
+($\sim 0.1$ W), on the other hand, generate new domains of coherences. Our
+results are applicable to a wide class of systems, and we specifically
+illustrate the remarkable sensing capabilities in the context of a weakly
+anharmonic Yttrium Iron Garnet (YIG) sphere interacting with a cavity via a
+tapered fiber waveguide. A small change in the anharmonicity leads to a
+substantial change in the induced spin current.",2010.12954v1
+2020-11-16,Electrically induced strong modulation of magnons transport in ultrathin magnetic insulator films,"Magnon transport through a magnetic insulator can be controlled by
+current-biased heavy-metal gates that modulate the magnon conductivity via the
+magnon density. Here, we report nonlinear modulation effects in 10$\,$nm thick
+yttrium iron garnet (YIG) films. The modulation efficiency is larger than
+40\%/mA. The spin transport signal at high DC current density (2.2$\times
+10^{11}\,$A/m$^{2}$) saturates for a 400$\,$nm wide Pt gate, which indicates
+that even at high current levels a magnetic instability cannot be reached in
+spite of the high magnetic quality of the films.",2011.07800v1
+2020-12-01,Magnon hybridization in ferrimagnetic heterostructures,"We study magnon hybridization in a ferrimagnetic heterostructure consisting
+of ultrathin gadolinium iron garnet and yttrium iron garnet layers and show the
+localized and extended spatial profiles of the magnon modes with different
+polarizations. These modes are expected to have distinct thermal excitation
+properties in the presence of a temperature gradient across the
+heterostructure. From a quantitative analysis of their consequences on
+longitudinal spin Seebeck effect, we predict an observable shift of the
+sign-changing temperature with respect to the one previously observed in
+gadolinium iron garnet. Moreover, the sign-changing point of spin Seebeck
+signal is found to be tunable by YIG thickness. Our results suggest the
+necessity of taking into account the temperature difference between the magnon
+modes in ferrimagnetic heterostructures.",2012.00576v1
+2020-12-01,Design of an optomagnonic crystal: towards optimal magnon-photon mode matching at the microscale,"We put forward the concept of an optomagnonic crystal: a periodically
+patterned structure at the microscale based on a magnetic dielectric, which can
+co-localize magnon and photon modes. The co-localization in small volumes can
+result in large values of the photon-magnon coupling at the single quanta
+level, which opens perspectives for quantum information processing and quantum
+conversion schemes with these systems. We study theoretically a simple geometry
+consisting of a one-dimensional array of holes with an abrupt defect,
+considering the ferrimagnet Yttrium Iron Garnet (YIG) as the basis material. We
+show that both magnon and photon modes can be localized at the defect, and use
+symmetry arguments to select an optimal pair of modes in order to maximize the
+coupling. We show that an optomagnonic coupling in the kHz range is achievable
+in this geometry, and discuss possible optimization routes in order to improve
+both coupling strengths and optical losses.",2012.00760v2
+2021-01-12,Temperature dependence of the mean magnon collision time in a spin Seebeck device,"Based on the relaxation time approximation, the mean collision time for
+magnon scattering $\tau_c(T)$ is computed from the experimental spin Seebeck
+coefficient of a bulk YIG / Pt bilayer. The scattering results to be composed
+by two processes: the low temperature one, with a $T^{-1/2}$ dependence, is
+attributed to the scattering by defects and provides a mean free path around 10
+$\mu$m; the high temperature one, depending on $T^{-4}$, is associated to the
+scattering by other magnons. The results are employed to predict the thickness
+dependence of the spin Seebeck coefficient for thin films.",2101.04405v1
+2021-01-25,Nonreciprocal Transmission and Entanglement in a cavity-magnomechanical system,"Quantum entanglement, a key element for quantum information is generated with
+a cavity-magnomechanical system. It comprises of two microwave cavities, a
+magnon mode and a vibrational mode, and the last two elements come from a YIG
+sphere trapped in the second cavity. The two microwave cavities are connected
+by a superconducting transmission line, resulting in a linear coupling between
+them. The magnon mode is driven by a strong microwave field and coupled to
+cavity photons via magnetic dipole interaction, and at the same time interacts
+with phonons via magnetostrictive interaction. By breaking symmetry of the
+configuration, we realize nonreciprocal photon transmission and one-way
+bipartite quantum entanglement. By using current experimental parameters for
+numerical simulation, it is hoped that our results may reveal a new strategy to
+built quantum resources for the realization of noise-tolerant quantum
+processors, chiral networks, and so on.",2101.09931v1
+2021-02-24,Phase-controlled pathway interferences and switchable fast-slow light in a cavity-magnon polariton system,"We study the phase controlled transmission properties in a compound system
+consisting of a 3D copper cavity and an yttrium iron garnet (YIG) sphere. By
+tuning the relative phase of the magnon pumping and cavity probe tones,
+constructive and destructive interferences occur periodically, which strongly
+modify both the cavity field transmission spectra and the group delay of light.
+Moreover, the tunable amplitude ratio between pump-probe tones allows us to
+further improve the signal absorption or amplification, accompanied by either
+significantly enhanced optical advance or delay. Both the phase and
+amplitude-ratio can be used to realize in-situ tunable and switchable fast-slow
+light. The tunable phase and amplitude-ratio lead to the zero reflection of the
+transmitted light and an abrupt fast-slow light transition. Our results confirm
+that direct magnon pumping through the coupling loops provides a versatile
+route to achieve controllable signal transmission, storage, and communication,
+which can be further expanded to the quantum regime, realizing coherent-state
+processing or quantum-limited precise measurements.",2102.12181v1
+2021-03-10,Experimental Demonstration of a Rowland Spectrometer for Spin Waves,"We experimentally demonstrate the operation of a spin-wave Rowland
+spectrometer. In the proposed device geometry, spin waves are coherently
+excited on a diffraction grating and form an interference pattern that
+spatially separates spectral components of the incoming signal. The diffraction
+grating was created by focused-ion-beam irradiation, which was found to locally
+eliminate the ferrimagnetic properties of YIG, without removing the material.
+We found that in our experiments spin waves were created by an indirect
+mechanism, by exploiting nonlinear resonance between the grating and the
+coplanar waveguide. Our work paves the way for complex spin-wave optic devices
+-- chips that replicate the functionality of integrated optical devices on a
+chip-scale.",2103.06165v1
+2021-04-11,Ultrafast Measurements of the Interfacial Spin Seebeck Effect in Au and Rare-Earth Iron Garnet Bilayers,"We investigate picosecond spin-currents across Au/iron-garnet interfaces in
+response to ultrafast laser heating of the electrons in the Au film. In the
+picoseconds after optical heating, interfacial spin currents occur due to an
+interfacial temperature difference between electrons in the metal and magnons
+in the insulator. We report measurements of this interfacial longitudinal spin
+Seebeck effect between Au and rare-earth iron-garnet insulators, i.e. RE$_3$
+Fe$_5$O$_{12}$, where RE is Y, Eu, Tb, Tm. We use time domain thermoreflectance
+(TDTR) measurements to characterize the thermal response of the bilayer to
+ultrafast optical heating. We use time-resolved magneto-optic Kerr effect
+(TR-MOKE) measurements of the Au layer to measure the time-evolution of spin
+accumulation in the Au film. We observe a spin Seebeck effect between Au/TmIG
+that is three times larger than for an Au/YIG bilayer. The interfacial thermal
+conductance between electrons in the Au and magnons in the TmIG layer is ~ 3
+$\frac{MW}{m^2 K}$.",2104.05075v2
+2021-05-06,Spin Wave Interference Detection via Inverse Spin Hall Effect,"In this letter, we present experimental data demonstrating spin wave
+interference detection using spin Hall effect (ISHE). Two coherent spin waves
+are excited in a yttrium-iron garnet (YIG) waveguide by continuous microwave
+signals. The initial phase difference between the spin waves is controlled by
+the external phase shifter. The ISHE voltage is detected at a distance of 2 mm
+and 4 mm away from the spin wave generating antennae by an attached Pt layer.
+Experimental data show ISHE voltage oscillation as a function of the phase
+difference between the two interfering spin waves. This experiment demonstrates
+an intriguing possibility of using ISHE in spin wave logic circuit converting
+spin wave phase into an electric signal",2105.02979v1
+2021-06-21,A low-loss ferrite circulator as a tunable chiral quantum system,"Ferrite microwave circulators allow one to control the directional flow of
+microwave signals and noise, and thus play a crucial role in present-day
+superconducting quantum technology. They are typically viewed as a black-box,
+and their internal structure is not specified, let alone used as a resource. In
+this work, we demonstrate a low-loss waveguide circulator constructed with
+single-crystalline yttrium iron garnet (YIG) in a 3D cavity, and analyze it as
+a multi-mode hybrid quantum system with coupled photonic and magnonic
+excitations. We show the coherent coupling of its chiral internal modes with
+integrated superconducting niobium cavities, and how this enables tunable
+non-reciprocal interactions between the intra-cavity photons. We also probe
+experimentally the effective non-Hermitian dynamics of this system and its
+effective non-reciprocal eigenmodes. The device platform provides a test bed
+for implementing non-reciprocal interactions in open-system circuit QED.",2106.11283v2
+2021-08-02,Spin Wave Computing using pre-recorded magnetization patterns,"We propose a novel type of a spin wave computing device, based on a bilayer
+structure which includes a bias layer, made from a hard magnetic material and a
+propagation layer, made from a magnetic material with low damping, for example,
+Yttrium Garnet (YiG) or Permalloy. The bias layer maintains a stable
+pre-recorded magnetization pattern, generating a bias field with a desired
+spatial dependence, which in turn sets the equilibrium magnetization inside the
+propagation layer. When an external source applies an RF field or spinwave to
+the propagation layer, excited spin waves scatter on the magnetization's
+inhomogenuities, resulting in a complex interference behavior. One thus has the
+ability to adjust spin wave propagation properties simply by altering the
+magnetization in the bias layer. We demonstrate that the phenomenon can be
+utilized to perform a variety of computational operations, including Fourier
+Transform, Vector-Matrix multiplication and Grover search algorithm, with the
+operational parameters exceeding conventional designs by orders of magnitude.",2108.00909v1
+2021-12-03,Microwave Amplification in a PT -symmetric-like Cavity Magnomechanical System,"We propose a scheme that can generate tunable magnomechanically induced
+amplification in a double-cavity parity-time-(PT -) symmetric-like
+magnomechanical system under a strong control and weak probe field. The system
+consists of a ferromagnetic-material yttrium iron garnet (YIG) sphere placed in
+a passive microwave cavity which is connected with another active cavity. We
+reveal that ideally induced amplification of the microwave probe signal may
+reach the maximum value 1000000 when cavity-cavity, cavity-magnon and
+magnomechanical coupling strengths are nonzero simultaneously. The phenomenon
+might have potential applications in the field of quantum information
+processing and quantum optical devices. Besides, we also find the phenomena of
+slow-light propagation. In this case, group speed delay of the light can
+achieve 0.000035s, which can enhance some nonlinear effect. Moreover, due to
+the relatively flat dispersion curve, the proposal may be applied to sensitive
+optical switches, which plays an important role in storing photons and quantum
+optical chips.",2112.01727v1
+2021-12-07,Coupling function from bath density of states,"Modelling of an open quantum system requires knowledge of parameters that
+specify how it couples to its environment. However, beyond relaxation rates,
+realistic parameters for specific environments and materials are rarely known.
+Here we present a method of inferring the coupling between a generic system and
+its bosonic (e.g., phononic) environment from the experimentally measurable
+density of states (DOS). With it we confirm that the DOS of the well-known
+Debye model for three-dimensional solids is physically equivalent to choosing
+an Ohmic bath. We further match a real phonon DOS to a series of Lorentzian
+coupling functions, allowing us to determine coupling parameters for gold,
+yttrium iron garnet (YIG) and iron as examples. The results illustrate how to
+obtain material-specific dynamical properties, such as memory kernels. The
+proposed method opens the door to more accurate modelling of relaxation
+dynamics, for example for phonon-dominated spin damping in magnetic materials.",2112.04001v2
+2021-12-08,Role of Magnon-Magnon Scattering in Magnon Polaron Spin Seebeck Effect,"The spin Seebeck effect (SSE) signal of magnon polarons in bulk-Y3Fe5O12
+(YIG)/Pt heterostructures is found to drastically change as a function of
+temperature. It appears as a dip in the total SSE signal at low temperatures,
+but as the temperature increases, the dip gradually decreases before turning to
+a peak. We attribute the observed dip-to-peak transition to the rapid rise of
+the four-magnon scattering rate. Our analysis provides important insights into
+the microscopic origin of the hybridized excitations and the overall
+temperature dependence of the SSE anomalies.",2112.04621v1
+2021-12-27,Observation of magnon cross-Kerr effect in cavity magnonics,"When there is a certain amount of field inhomogeneity, the biased
+ferrimagnetic crystal will exhibit the higher-order magnetostatic (HMS) mode in
+addition to the uniform-precession Kittel mode. In cavity magnonics, we show
+both experimentally and theoretically the cross-Kerr-type interaction between
+the Kittel mode and HMS mode. When the Kittel mode is driven to generate a
+certain number of excitations, the HMS mode displays a corresponding frequency
+shift and vice versa. The cross-Kerr effect is caused by an exchange
+interaction between these two spin-wave modes. Utilizing the cross-Kerr effect,
+we realize and integrate a multi-mode cavity magnonic system with only one
+yttrium iron garnet (YIG) sphere. Our results will bring new methods to
+magnetization dynamics studies and pave a way for novel cavity magnonic devices
+by including the magnetostatic mode-mode interaction as an operational degree
+of freedom.",2112.13807v1
+2022-01-11,Edge spin wave transmission through a vertex domain wall in triangular dots,"Spin waves (SWs), being usually reflected by domain walls, could also be
+channeled along them. Edge domain walls yield the interesting, and potentially
+applicable to real devices property of broadband spin waves confinement to the
+edges of the structure. Here we investigate through numerical simulations the
+propagation of quasi one-dimensional spin waves in triangle-shaped amorphous
+YIG ($Y_3Fe_5O_{12}$) micron sized ferromagnets as a function of the angle
+aperture. The edge spin waves (ESWs) have been propagated over the corner in
+triangles of 2 microns side with a fixed thickness of 85 nm. Parameters such as
+superior vertex angle (in the range of 40$^\circ$-75$^\circ$) and applied
+magnetic field have been optimized in order to obtain a higher transmission
+coefficient of the ESWs over the triangle vertex. We observed that for a
+certain aperture angle for which dominated ESW frequency coincides with one of
+the localised DW modes, the transmission is maximized near one and the phase
+shift drops to $\pi/2$ indicating resonant transmission of ESWs through the
+upper corner. We compare the obtained results with existing theoretical models.
+These results could contribute to the development of novel basic elements for
+spin wave computing.",2201.04054v2
+2022-01-11,Building instructions for a ferromagnetic axion haloscope,"A ferromagnetic haloscope is a rf spin-magnetometer used for searching Dark
+Matter in the form of axions. A magnetic material is monitored searching for
+anomalous magnetization oscillations which can be induced by dark matter
+axions. To properly devise such instrument one first needs to understand the
+features of the searched-for signal, namely the effective rf field of dark
+matter axions $B_a$ acting on electronic spins. Once the properties of $B_a$
+are defined, the design and test of the apparatus may start. The optimal sample
+is a narrow linewidth and high spin-density material such as Yttrium Iron
+Garnet (YIG), coupled to a microwave cavity with almost matched linewidth to
+collect the signal. The power in the resonator is collected with an antenna and
+amplified with a Josephson Parametric amplifier, a quantum-limited device
+which, however, adds most of the setup noise. The signal is further amplified
+with low noise HEMT and down-converted for storage with an heterodyne receiver.
+This work describes how to build such apparatus, with all the experimental
+details, the main issues one might face, and some solutions.",2201.04081v1
+2022-02-06,Coexistence of coupling-induced transparency and absorption of transmission signals in magnon-mediated photon-photon coupling,"Coexistence of coupling-induced transparency (CIT) and absorption (CIA) of
+signals in magnon-mediated photon-photon coupling was experimentally determined
+in a planar hybrid structure consisting of a yttrium iron garnet (YIG) film and
+three concentric inverted-split-ring resonators (ISRRs). The experimental
+observation of simultaneous CIT and CIA phenomena was ascribed to
+magnon-mediated photon-photon coupling between the individually decoupled
+ISRRs. In order to capture the generic physics of the observed interactions, we
+constructed an appropriate analytical model based on the balance between the
+coherent and dissipative multiple-paths interactions, which model precisely
+reproduced both the CIT and CIA experimentally observed from a single hybrid
+system. This work, promisingly, can provide guidance for design of efficient,
+flexible, and well-controllable photon-magnonic devices that are highly in
+demand for applications to quantum technologies currently under development.",2202.02667v1
+2022-02-07,Magnetization dynamics affected by phonon pumping,"""Pumping"" of phonons by a dynamic magnetization promises to extend the range
+and functionality of magnonic devices. We explore the impact of phonon pumping
+on room-temperature ferromagnetic resonance (FMR) spectra of bilayers of thin
+yttrium iron garnet (YIG) films on thick gadolinium gallium garnet substrates
+over a wide frequency range. At low frequencies the Kittel mode hybridizes
+coherently with standing ultrasound waves of a bulk acoustic resonator to form
+magnon polarons that induce rapid oscillations of the magnetic susceptibility,
+as reported before. At higher frequencies, the phonon resonances overlap,
+merging into a conventional FMR line, but with an increased line width. The
+frequency dependence of the increased line broadening follows the predictions
+from phonon pumping theory in the thick substrate limit. In addition, we find
+substantial magnon-phonon coupling of a perpendicular standing spin wave (PSSW)
+mode. This evidences the importance of the mode overlap between the acoustic
+and magnetic modes, and provides a route towards engineering the magnetoelastic
+mode coupling.",2202.03331v1
+2022-03-30,Hybrid magnonics for short-wavelength spin waves facilitated by a magnetic heterostructure,"Recent research on hybrid magnonics has been restricted by the long magnon
+wavelengths of the ferromagnetic resonance modes. We present an experiment on
+the hybridization of 250-nm wavelength magnons with microwave photons in a
+multimode magnonic system consists of a planar cavity and a magnetic bilayer.
+The coupling between magnon modes in the two magnetic layers, i.e., the uniform
+mode in Permalloy (Py) and the perpendicular standing spin waves (PSSWs) in
+YIG, serves as an effective means for exciting short-wavelength PSSWs, which is
+further hybridized with the photon mode of the microwave resonator. The
+demonstrated magnon-photon coupling approaches the superstrong coupling regime,
+and can even be achieved near zero bias field.",2203.16310v1
+2022-04-14,Micro magnet location using spin waves,"In this work, we present experimental data demonstrating the feasibility of
+magnetic object location using spin waves. The test structure includes a
+Y$_3$Fe$_2$(FeO$_4$)$_3$) (YIG) film with four micro-antennas placed on the
+edges. A constant in-plane bias magnetic field is provided by NdFeB permanent
+magnet. Two antennas are used for spin wave excitation while the other two are
+used for the inductive voltage measurement. There are nine selected places for
+the magnet on the film. The magnet was subsequently placed in all nine
+positions and spin wave transmission and reflection were measured. The obtained
+experimental data show the difference in the output signal amplitude depending
+on the magnet position. All nine locations can be identified by the frequency
+and the amplitude of the absolute minimum in the output power. All experiments
+are accomplished at room temperature. Potentially, spin waves can be utilized
+for remote magnetic bit read-out. The disadvantages and physical constraints of
+this approach are also discussed.",2204.07238v1
+2022-06-02,Bistability in dissipatively coupled cavity magnonics,"Dissipative coupling of resonators arising from their cooperative dampings to
+a common reservoir induces intriguingly new physics such as energy level
+attraction. In this study, we report the nonlinear properties in a
+dissipatively coupled cavity magnonic system. A magnetic material YIG (yttrium
+iron garnet) is placed at the magnetic field node of a Fabry-Perot-like
+microwave cavity such that the magnons and cavity photons are dissipatively
+coupled. Under high power excitation, a nonlinear effect is observed in the
+transmission spectra, showing bistable behaviors. The observed bistabilities
+are manifested as clockwise, counterclockwise, and butterfly-like hysteresis
+loops with different frequency detuning. The experimental results are well
+explained as a Duffing oscillator dissipatively coupled with a harmonic one and
+the required trigger condition for bistability could be determined
+quantitatively by the coupled oscillator model. Our results demonstrate that
+the magnon damping has been suppressed by the dissipative interaction, which
+thereby reduces the threshold for conventional magnon Kerr bistability. This
+work sheds light upon potential applications in developing low power
+nonlinearity devices, enhanced anharmonicity sensors and for exploring the
+non-Hermitian physics of cavity magnonics in the nonlinear regime.",2206.01231v1
+2022-06-26,Tripartite high-dimensional magnon-photon entanglement in PT -symmetry broken phases of a non-Hermitian hybrid system,"Hybrid systems that combine spin ensembles and superconducting circuits
+provide a promising platform for implementing quantum information processing.
+We propose a non-Hermitian magnoncircuit-QED hybrid model consisting of two
+cavities and an yttrium iron garnet (YIG) sphere placed in one of the cavities.
+Abundant exceptional points (EPs), parity-time (PT )-symmetry phases and PT
+-symmetry broken phases are investigated in the parameter space. Tripartite
+highdimensional entangled states can be generated steadily among modes of the
+magnon and photons in PT -symmetry broken phases, corresponding to which the
+stable quantum coherence exists. Results show that the tripartite
+high-dimensional entangled state is robust against the dissipation of hybrid
+system, independent of a certain initial state, and insensitive to the
+fluctuation of magnonphoton coupling. Further, we propose to simulate the
+hybrid model with an equivalent LCR circuit. This work may provide prospects
+for realizing multipartite high-dimensional entangled states in the
+magnon-circuit-QED hybrid system.",2206.12769v1
+2022-06-29,Mechanical Bistability in Kerr-modified Cavity Magnomechanics,"Bistable mechanical vibration is observed in a cavity magnomechanical system,
+which consists of a microwave cavity mode, a magnon mode, and a mechanical
+vibration mode of a ferrimagnetic yttrium-iron-garnet (YIG) sphere. The
+bistability manifests itself in both the mechanical frequency and linewidth
+under a strong microwave drive field, which simultaneously activates three
+different kinds of nonlinearities, namely, magnetostriction, magnon self-Kerr,
+and magnon-phonon cross-Kerr nonlinearities. The magnon-phonon cross-Kerr
+nonlinearity is first predicted and measured in magnomechanics. The system
+enters a regime where Kerr-type nonlinearities strongly modify the conventional
+cavity magnomechanics that possesses only a radiation-pressure-like
+magnomechanical coupling. Three different kinds of nonlinearities are
+identified and distinguished in the experiment. Our work demonstrates a new
+mechanism for achieving mechanical bistability by combining magnetostriction
+and Kerr-type nonlinearities, and indicates that such Kerr-modified cavity
+magnomechanics provides a unique platform for studying many distinct
+nonlinearities in a single experiment.",2206.14588v2
+2022-06-30,Second order nonlinearity induced multipartite entanglement in a hybrid magnon cavity QED system,"We present a proposal to produce bipartite and tripartite entanglement in a
+hybrid magnon-cavity QED system. Two macroscopic yttrium iron garnet (YIG)
+spheres are coupled to a single-mode microwave cavity via magnetic dipole
+interaction, while the cavity photons are generated via the two photon process
+induced by a pump field. Using the mean field theory, we show that the second
+order nonlinearity can result in strong bipartite entanglement between cavity
+photons and magnonic modes under two conditions, i.e., $\delta_c
+\delta_{m}=2g^2$ and $\delta_c=-\delta_{m}$. For the later one, we also show
+the possibility for producing the bipartite entanglement between two magnonic
+modes and tripartite entanglement among the cavity photons and two magnonic
+modes. Combining these two conditions, we further derive a third condition,
+i.e., $\delta_m^2-\phi^2+2g^2=0$, where the tripartite entanglement can be
+achieved when two magnonic modes have different resonant frequencies.",2206.15326v1
+2022-08-02,Finite-frequency spin conductance of a ferro-/ferrimagnetic-insulator|normal-metal interface,"The interface between a ferro-/ferrimagnetic insulator and a normal metal can
+support spin currents polarized collinear with and perpendicular to the
+magnetization direction. The flow of angular momentum perpendicular to the
+magnetization direction (""transverse"" spin current) takes place via spin torque
+and spin pumping. The flow of angular momentum collinear with the magnetization
+(""longitudinal"" spin current) requires the excitation of magnons. In this
+article we extend the existing theory of longitudinal spin transport [Bender
+and Tserkovnyak, Phys. Rev. B 91, 140402(R) (2015)] in the zero-frequency
+weak-coupling limit in two directions: We calculate the longitudinal spin
+conductance non-perturbatively (but in the low-frequency limit) and at finite
+frequency (but in the limit of low interface transparency). For the
+paradigmatic spintronic material system YIG|Pt, we find that non-perturbative
+effects lead to a longitudinal spin conductance that is ca. 40% smaller than
+the perturbative limit, whereas finite-frequency corrections are relevant at
+low temperatures < 100 K only, when only few magnon modes are thermally
+occupied.",2208.01420v1
+2022-09-19,Cavity-mediated superconductor$\unicode{x2013}$ferromagnetic insulator coupling,"A recent proof of concept showed that cavity photons can mediate
+superconducting (SC) signatures to a ferromagnetic insulator (FI) over a
+macroscopic distance [Phys. Rev. B, 102, 180506(R) (2020)]. In contrast with
+conventional proximity systems, this facilitates long-distance
+FI$\unicode{x2013}$SC coupling, local subjection to different drives and
+temperatures, and studies of their mutual interactions without proximal
+disruption of their orders. Here we derive a microscopic theory for these
+interactions, with an emphasis on the leading effect on the FI, namely, an
+induced anisotropy field. In an arbitrary practical example, we find an
+anisotropy field of $14 \unicode{x2013} 16$ $\mu$T, which is expected to yield
+an experimentally appreciable tilt of the FI spins for low-coercivity FIs such
+as Bi-YIG. We discuss the implications and potential applications of such a
+system in the context of superconducting spintronics.",2209.09308v2
+2022-11-10,High wave vector non-reciprocal spin wave beams,"We report unidirectional transmission of micron-wide spin waves beams in a 55
+nm thin YIG. We downscaled a chiral coupling technique implementing Ni80Fe20
+nanowires arrays with different widths and lattice spacing to study the
+non-reciprocal transmission of exchange spin waves down to lambda = 80 nm. A
+full spin wave spectroscopy analysis of these high wavevector coupled-modes
+shows some difficulties to characterize their propagation properties, due to
+both the non-monotonous field dependence of the coupling efficiency, and also
+the inhomogeneous stray field from the nanowires.",2211.05514v2
+2023-02-17,Entangling ferrimagnetic magnons with an atomic ensemble via opto-magnomechanics,"We show how to prepare macroscopic entanglement between an atomic ensemble
+and a large number of magnons in a ferrimagnetic YIG crystal. Specifically, we
+adopt an opto-magnomechanical configuration where the magnetostriction-induced
+magnomechanical displacement couples to an optical cavity via radiation
+pressure, and the latter further couples to an ensemble of two-level atoms that
+are placed inside the cavity. We show that by properly driving the cavity and
+magnon modes, optomechanical entanglement is created which is further
+distributed to the atomic and magnonic systems, yielding stationary
+entanglement between atoms and magnons. The atom-magnon entanglement is a
+result of the combined effect of opto- and magnomechanical cooling and
+optomechanical parametric down-conversion interactions. A competition mechanism
+between two mechanical cooling channels is revealed. We further show that
+genuine tripartite entanglement of three massive subsystems, i.e., atoms,
+magnons and phonons, can also be achieved in the same system. Our results
+indicate that the hybrid opto-magnomechanical system may become a promising
+system for preparing macroscopic quantum states involving magnons, photons,
+phonons and atoms.",2302.08684v2
+2023-02-21,Aluminium substituted yttrium iron garnet thin films with reduced Curie temperature,"Magnetic garnets such as yttrium iron garnet (Y$_3$Fe$_5$O$_{12}$, YIG) are
+widely used in spintronic and magnonic devices. Their magnetic and
+magneto-optical properties can be modified over a wide range by tailoring their
+chemical composition. Here, we report the successful growth of Al-substituted
+yttrium iron garnet (YAlIG) thin films via radio frequency sputtering in
+combination with an ex situ annealing step. Upon selecting appropriate process
+parameters, we obtain highly crystalline YAlIG films with different Al$^{3+}$
+substitution levels on both, single crystalline Y$_3$Al$_5$O$_{12}$ (YAG) and
+Gd$_3$Ga$_5$O$_{12}$ (GGG) substrates. With increasing Al$^{3+}$ substitution
+levels, we observe a reduction of the saturation magnetisation as well as a
+systematic decrease of the magnetic ordering temperature to values well below
+room temperature. YAlIG thin films thus provide an interesting material
+platform for spintronic and magnonic experiments in different magnetic phases.",2302.10517v2
+2023-03-20,Secondary Excitation of Spin-Waves: How Electromagnetic Cross-Talk Impacts on Magnonic Devices,"This work examines the impact of electromagnetic cross-talk in magnonic
+devices when using inductive spin-wave (SW) transducers. We present detailed
+electrical SW spectroscopy measurements showing the signal contributions to be
+considered in magnonic device design. We further provide a rule of thumb
+estimation for the cross-talk that is responsible for the secondary SW
+excitation at the output transducer. Simulations and calibrated electrical
+characterizations underpin this method. Additionally, we visualize the
+secondary SW excitation via time-resolved MOKE imaging in the forward-volume
+configuration in a 100nm Yttrium-Iron-Garnet (YIG) system. Our work is a step
+towards fast yet robust joint electromagentic-micromagnetic magnonic device
+design.",2303.11303v2
+2023-03-26,Compact localised states in magnonic Lieb lattices,"Lieb lattice is one of the simplest bipartite lattices where compact
+localized states (CLS) are observed. This type of localisation is induced by
+the peculiar topology of the unit cell, where the modes are localized only on
+one sublattice due to the destructive interference of partial waves. The CLS
+exist in the absence of defects and are associated with the flat bands in the
+dispersion relation. The Lieb lattices were successfully implemented as optical
+lattices or photonic crystals. This work demonstrates the possibility of
+magnonic Lieb lattice realization where the flat bands and CLS can be observed
+in the planar structure of sub-micron in-plane sizes. Using forward volume
+configuration, we investigated numerically (using the finite element method)
+the Ga-dopped YIG layer with cylindrical inclusions (without Ga content)
+arranged in a Lieb lattice of the period 250 nm. We tailored the structure to
+observe, for the few lowest magnonic bands, the oscillatory and evanescent spin
+waves in inclusions and matrix, respectively. Such a design reproduces the Lieb
+lattice of nodes (inclusions) coupled to each other by the matrix with the CLS
+in flat bands.",2303.14843v1
+2023-03-27,Temperature dependent study of the spin dynamics of coupled Y$_3$Fe$_5$O$_{12}$/Gd$_3$Fe$_5$O$_{12}$/Pt trilayers,"In this study, we investigate the dynamic response of a Y$_3$Fe$_5$O$_{12}$
+(YIG)/ Gd$_3$Fe$_5$O$_{12}$ (GdIG)/ Pt trilayer system by measurements of the
+ferromagnetic resonance (FMR) and the pumped spin current detected by the
+inverse spin Hall effect. This trilayer system offers the unique opportunity to
+investigate the spin dynamics of the ferrimagnetic GdIG, close to its
+compensation temperature. We show that our trilayer acts as a highly tunable
+spin current source. Our experimental results are supported by micro-magnetic
+simulations. As the detected spin current in the top Pt layer is distinctly
+dominated by the GdIG layer, this gives the unique opportunity to investigate
+the excitation and dynamic properties of GdIG while comparing it to the
+broadband FMR absorption spectrum of the heterostructure.",2303.15085v1
+2023-04-04,Full quantum theory for magnon transport in two-sublattice magnetic insulators and magnon junctions,"Magnon, as elementary excitation in magnetic systems, can carry and transfer
+angular momentum. Due to the absence of Joule heat during magnon transport,
+researches on magnon transport have gained considerable interests over the past
+decade. Recently, a full quantum theory has been employed to investigate magnon
+transport in ferromagnetic insulators (FMIs). However, the most commonly used
+magnetic insulating material in experiments, yttrium iron garnet (YIG), is a
+ferrimagnetic insulator (FIMI). Therefore, a full quantum theory for magnon
+transport in FIMI needs to be established. Here, we propose a Green's function
+formalism to compute the magnon bulk and interface current in both FIMIs and
+antiferromagnetic insulators (AFMIs). We investigate the spatial distribution
+and temperature dependence of magnon current in FIMIs and AFMIs generated by
+temperature or spin chemical potential step. In AFMIs, magnon currents
+generated by temperature step in the two sublattices cancel each other out.
+Subsequently, we numerically simulate the magnon junction effect using the
+Green's function formalism, and result shows near 100\% magnon junction ratio.
+This study demonstrates the potential for investigating magnon transport in
+specific magnonic devices using a full quantum theory.",2304.01930v1
+2023-04-19,Nonreciprocal ultrastrong magnon-photon coupling in the bandgap of photonic crystals,"We observe a nonreciprocal ultrastrong magnon-photon coupling in the bandgap
+of photonic crystals by introducing a single crystal YIG cylinder into copper
+photonic crystals cavity as a point defect. The coupling strength reaches up to
+1.18 GHz, which constitutes about 10.9% of the photon energy compared to the
+photon frequency around 10.8 GHz. It is fascinating that the coupling achieves
+unidirectional signal transmission in the whole bandgap. This study
+demonstrates the possibility of controlling nonreciprocal magnon-photon
+coupling by manipulating the structure of photonic crystals, providing new
+methods to investigate the influence of magnetic point defects on microwave
+signal transmission.",2304.09627v1
+2023-04-26,Critical Cavity-Magnon Polariton Mediated Strong Long-Distance Spin-Spin Coupling,"Strong long-distance spin-spin coupling is desperately demanded for
+solid-state quantum information processing, but it is still challenged. Here,
+we propose a hybrid quantum system, consisting of a coplanar waveguide (CPW)
+resonator weakly coupled to a single nitrogen-vacancy spin in diamond and a
+yttrium-iron-garnet (YIG) nanosphere holding Kerr magnons, to realize strong
+long-distance spin-spin coupling. With a strong driving field on magnons, the
+Kerr effect can squeeze magnons, and thus exponentially enhance the coupling
+between the CPW resonator and the squeezed magnons, which produces two
+cavity-magnon polaritons, i.e., the high-frequency polariton (HP) and
+low-frequency polariton (LP). When the enhanced cavity-magnon coupling
+approaches to the critical value, the spin is fully decoupled from the HP,
+while the coupling between the spin and the LP is significantly improved. In
+the dispersive regime, a strong spin-spin coupling is achieved with accessible
+parameters, and the coupling distance can be up to $\sim$cm. Our proposal
+provides a promising way to manipulate remote solid spins and perform quantum
+information processing in weakly coupled hybrid systems.",2304.13553v2
+2023-05-10,Proposal for optomagnonic teleportation and entanglement swapping,"A protocol for realizing discrete-variable quantum teleportation in an
+optomagnonic system is provided. Using optical pulses, an arbitrary photonic
+qubit state encoded in orthogonal polarizations is transferred onto the joint
+state of a pair of magnonic oscillators in two macroscopic yttrium-iron-garnet
+(YIG) spheres that are placed in an optical interferometer. We further show
+that optomagnonic entanglement swapping can be realized in an extended
+dual-interferometer configuration with a joint Bell-state detection.
+Consequently, magnon Bell states are prepared. We analyze the effect of the
+residual thermal occupation of the magnon modes on the fidelity in both the
+teleportation and entanglement swapping protocols.",2305.05889v1
+2023-05-19,Quantum transduction of superconducting qubit in electro-optomechanical and electro-optomagnonical system,"We study the quantum transduction of a superconducting qubit to an optical
+photon in electro-optomechanical and electro-optomagnonical systems. The
+electro-optomechanical system comprises a flux-tunable transmon qubit coupled
+to a suspended mechanical beam, which then couples to an optical cavity.
+Similarly, in an electro-optomagnonical system, a flux-tunable transmon qubit
+is coupled to an optical whispering gallery mode via a magnon excitation in a
+YIG ferromagnetic sphere. In both systems, the transduction process is done in
+sequence. In the first sequence, the qubit states are encoded in coherent
+excitations of phonon/magnon modes through the phonon/magnon-qubit interaction,
+which is non-demolition in the qubit part. We then measure the phonon/magnon
+excitations, which reveal the qubit states, by counting the average number of
+photons in the optical cavities. The measurement of the phonon/magnon
+excitations can be performed at a regular intervals of time.",2305.11629v1
+2023-07-18,Distant entanglement via photon hopping in a coupled magnomechanical system,"We theoretically propose a scheme to generate distant bipartite entanglement
+between various subsystems in coupled magnomechanical systems where both the
+microwave cavities are coupled through single photon hopping parameter. Each
+cavity also contains a magnon mode and phonon mode and this gives five
+excitation modes in our model Hamiltonian which are cavity-1 photons, cavity-2
+photons, magnon, and phonon modes in both YIG spheres. We found that
+significant bipartite entanglement exists between indirectly coupled subsystems
+in coupled microwave cavities for an appropriate set of parameters regime.
+Moreover, we also obtain suitable cavity and magnon detuning parameters for a
+significant distant bipartite entanglement in different bipartitions. In
+addition, it can be seen that a single photon hopping parameter significantly
+affects both the degree as well as the transfer of quantum entanglement between
+various bipartitions. Hence, our present study related to coupled microwave
+cavity magnomechanical configuration will open new perspectives in coherent
+control of various quantum correlations including quantum state transfer among
+macroscopic quantum systems",2307.09424v1
+2023-07-19,Enhanced bipartite entanglement and Gaussian quantum steering of squeezed magnon modes,"We theoretically investigate a scheme to entangle two squeezed magnon modes
+in a double cavitymagnon system, where both cavities are driven by a two-mode
+squeezed vacuum microwave field. Each cavity contains an optical parametric
+amplifier as well as a macroscopic yttrium iron garnet (YIG) sphere placed near
+the maximum bias magnetic fields such that this leads to the excitation of the
+relevant magnon mode and its coupling with the corresponding cavity mode. We
+have obtained optimal parameter regimes for achieving the strong magnon-magnon
+entanglement and also studied the effectiveness of this scheme towards the
+mismatch of both the cavity-magnon couplings and decay parameters. We have also
+explored the entanglement transfer efficiency including Gaussian quantum
+steering in our proposed system",2307.09846v1
+2023-08-11,Kerr nonlinearity induced strong spin-magnon coupling,"One pillar of quantum magnonics is the exploration of the utilization of the
+mediation role of magnons in different platforms to develop quantum
+technologies. The efficient coupling between magnons and various quantum
+entities is a prerequisite. Here, we propose a scheme to enhance the
+spin-magnon coupling by the magnonic Kerr nonlinearity in a YIG sphere. We find
+that the Kerr-enhanced spin-magnon coupling invalidates the widely used
+single-Kittel-mode approximation to magnons. It is revealed that the spin
+decoherence induced by the multimode magnons in the strong-coupling regime
+becomes not severe, but suppressed, manifesting as either population trapping
+or persistent Rabi-like oscillation. This anomalous effect is because the spin
+changes to be so hybridized with the magnons that one or two bound states are
+formed between them. Enriching the spin-magnon coupling physics, the result
+supplies a guideline to control the spin-magnon interface.",2308.05927v2
+2023-08-15,Global biasing using a Hardware-based artificial Zeeman term in Spinwave Ising Machines,"A spinwave Ising machine (SWIM) is a newly proposed type of time-multiplexed
+hardware solver for combinatorial optimization that employs feedback coupling
+and phase sensitive amplification to map an Ising Hamiltonian into
+phase-binarized propagating spin-wave RF pulses in an Yttrium-Iron-Garnet (YIG)
+film. In this work, we increase the mathematical complexity of the SWIM by
+adding a global Zeeman term to a 4-spin MAX-CUT Hamiltonian using a continuous
+external electrical signal with the same frequency as the spin pulses and phase
+locked with with one of the two possible states. We are able to induce
+ferromagnetic ordering in both directions of the spin states despite
+antiferromagnetic pairwise coupling. Embedding a planar antiferromagnetic spin
+system in a magnetic field has been proven to increase the complexity of the
+graph associated to its Hamiltonian and thus this straightforward
+implementation helps explore higher degrees of complexity in this evolving
+solver.",2308.07718v1
+2023-08-28,Spin wave mode conversion in an in-plane magnetized microscale T-shaped YIG magnonic splitter,"As one of the fundamental magnonic devices, a magnonic splitter device has
+been proposed and spin wave propagation in this device has been studied
+numerically and experimentally. In the present work, we fabricated a T-shaped
+magnonic splitter with 6 $\mu$m-wide three arms using a 100 nm-thick yttrium
+iron garnet film and, using time-resolved magneto-optic Kerr microscopy,
+observed that spin waves split into both, the vertical and the horizontal
+direction at the junction. Analyzing the results, we found that spin wave modes
+are converted into another during the splitting process and the splitting
+efficiency is dominantly dependent on the 1st order of incoming spin waves.",2308.14327v1
+2023-09-28,Engineering Entangled Coherent States of Magnons and Phonons via a Transmon Qubit,"We propose a scheme for generating and controlling entangled coherent states
+(ECS) of magnons, i.e. the quanta of the collective spin excitations in
+magnetic systems, or phonons in mechanical resonators. The proposed hybrid
+circuit architecture comprises a superconducting transmon qubit coupled to a
+pair of magnonic Yttrium Iron Garnet (YIG) spherical resonators or mechanical
+beam resonators via flux-mediated interactions. Specifically, the coupling
+results from the magnetic/mechanical quantum fluctuations modulating the qubit
+inductor, formed by a superconducting quantum interference device (SQUID). We
+show that the resulting radiation-pressure interaction of the qubit with each
+mode, can be employed to generate maximally-entangled states of magnons or
+phonons. In addition, we numerically demonstrate a protocol for the preparation
+of magnonic and mechanical Bell states with high fidelity including realistic
+dissipation mechanisms. Furthermore, we have devised a scheme for reading out
+the prepared states using standard qubit control and resonator field
+displacements. Our work demonstrates an alternative platform for quantum
+information using ECS in hybrid magnonic and mechanical quantum networks.",2309.16514v1
+2023-10-09,Bath-induced spin inertia,"Spin dynamics is usually described as massless or, more precisely, as free of
+inertia. Recent experiments, however, found direct evidence for inertial spin
+dynamics. In turn, it is necessary to rethink the basics of spin dynamics.
+Focusing on a macrospin in an environment (bath), we show that the spin-to-bath
+coupling gives rise to spin inertia. This bath-induced spin inertia appears
+universally from all the high-frequency bath modes. We expect our results to
+provide new insights into recent experiments on spin inertia. Moreover, they
+indicate that any channel for spin dissipation should also be accompanied by a
+term accounting for bath-induced spin inertia. As an illustrative example, we
+consider phonon-bath-induced spin inertia in a YIG/GGG stack.",2310.05621v2
+2023-11-30,Nanoscaled magnon transistor based on stimulated three-magnon splitting,"Magnonics is a rapidly growing field, attracting much attention for its
+potential applications in data transport and processing. Many individual
+magnonic devices have been proposed and realized in laboratories. However, an
+integrated magnonic circuit with several separate magnonic elements has yet not
+been reported due to the lack of a magnonic amplifier to compensate for
+transport and processing losses. The magnon transistor reported in [Nat.
+Commun. 5, 4700, (2014)] could only achieve a gain of 1.8, which is
+insufficient in many practical cases. Here, we use the stimulated three-magnon
+splitting phenomenon to numerically propose a concept of magnon transistor in
+which the energy of the gate magnons at 14.6 GHz is directly pumped into the
+energy of the source magnons at 4.2 GHz, thus achieving the gain of 9. The
+structure is based on the 100 nm wide YIG nano-waveguides, a directional
+coupler is used to mix the source and gate magnons, and a dual-band magnonic
+crystal is used to filter out the gate and idler magnons at 10.4 GHz frequency.
+The magnon transistor preserves the phase of the signal and the design allows
+integration into a magnon circuit.",2311.18479v1
+2023-12-14,Magnetization Reversal of 50-nm-wide Ni81Fe19 Nanostripes by Ultrashort Magnons in Yttrium Iron Garnet for Memory-Enhanced Magnonic Circuits,"Spin waves (magnons) can enable wave-based neuromorphic computing by which
+one aims at overcoming limitations inherent to conventional electronics and the
+von Neumann architecture. In this study, we explore the storage of magnon
+signals and the magnetization switching of periodic and aperiodic arrays of
+Ni81Fe19 (Py) nanostripes with widths (w) between 50 nm and 200 nm. Spin waves
+excited with low microwave power in yttrium iron garnet induce the reversal of
+the nanostripes of different w in a small opposing field. Exploiting
+microwave-to-magnon transducers for magnon modes with ultrashort wavelengths,
+we demonstrate the reversal of 50-nm-wide Py nanostripes by magnons with
+wavelength ~ 100 nm after they have propagated over 25 micrometer in YIG. The
+findings are important for designing a magnon-based in-memory computing device.",2312.09177v1
+2023-12-17,An Edge-Coupled Magnetostatic Bandpass Filter,"This paper reports on the design, fabrication, and characterization of an
+edge-coupled magnetostatic forward volume wave bandpass filter. Using
+micromachining techniques, the filter is fabricated from a yttrium iron garnet
+(YIG) film grown on a gadolinium gallium garnet (GGG) substrate with inductive
+transducers. By adjusting an out-of-plane magnetic field, we demonstrate linear
+center frequency tuning for a $4^{\text{th}}$-order filter from 4.5 GHz to 10.1
+GHz while retaining a fractional bandwidth of 0.3%, an insertion loss of 6.94
+dB, and a -35dB rejection. We characterize the filter nonlinearity in the
+passband and stopband with IIP3 measurements of -4.85 dBm and 25.84 dBm,
+respectively. When integrated with a tunable magnetic field, this device is an
+octave tunable narrowband channel-select filter.",2312.10583v1
+2023-12-20,Non-equilibrium criticality at the onset of time-crystalline order in $O(N)$ models,"We explore the phase transitions at the onset of time-crystalline order in
+$O(N)$ models driven out-of-equilibrium. The spontaneous breaking of time
+translation symmetry and its Goldstone mode are captured by an effective
+description with $O(N)\times SO(2)$ symmetry. Using the renormalization group
+and the $\epsilon=4-d$ expansion in a leading two-loop analysis, we identify a
+new non-equilibrium universality class. Strikingly, it controls the
+long-distance physics no matter how small the microscopic breaking of
+equilibrium conditions is. The $O(N=2)\times SO(2)$ symmetry group is realized
+for magnon condensation in pumped yttirum iron garnet (YIG) films and in
+exciton-polariton systems with a polarization degree of freedom.",2312.13372v1
+2024-01-22,Theory of momentum-resolved magnon electron energy loss spectra: The case of Yttrium Iron Garnet,"We explore the inelastic spectra of electrons impinging in a magnetic system.
+The methodology here presented is intended to highlight the charge-dependent
+interaction of the electron beam in a STEM-EELS experiment, and the local
+vector potential generated by the magnetic lattice. This interaction shows an
+intensity $10^{-2}$ smaller than the purely spin interaction, which is taken to
+be functionally the same as in the inelastic neutron experiment. On the other
+hand, it shows a strong scattering vector dependence ($\kappa^{-4}$) and a
+dependence with the relative orientation between the probe wavevector and the
+local magnetic moments of the solid. We present YIG as a case study due to its
+high interest by the community.",2401.12302v2
+2024-01-30,Entropy production rate and correlations of cavity magnomechanical system,"We present the irreversibility generated by a stationary cavity
+magnomechanical system composed of a yttrium iron garnet (YIG) sphere with a
+diameter of a few hundred micrometers inside a microwave cavity. In this
+system, the magnons, i.e., collective spin excitations in the sphere, are
+coupled to the cavity photon mode via magnetic dipole interaction and to the
+phonon mode via magnetostrictive force (optomechanical-like). We employ the
+quantum phase space formulation of the entropy change to evaluate the
+steady-state entropy production rate and associated quantum correlation in the
+system. We find that the behavior of the entropy flow between the cavity photon
+mode and the phonon mode is determined by the magnon-photon coupling and the
+cavity photon dissipation rate. Interestingly, the entropy production rate can
+increase/decrease depending on the strength of the magnon-photon coupling and
+the detuning parameters. We further show that the amount of correlations
+between the magnon and phonon modes is linked to the irreversibility generated
+in the system for small magnon-photon coupling. Our results demonstrate the
+possibility of exploring irreversibility in driven magnon-based hybrid quantum
+systems and open a promising route for quantum thermal applications.",2401.16857v1
+2024-02-07,Breaking surface plasmon excitation constraint via surface spin waves,"Surface plasmons in two-dimensional (2D) electron systems have attracted
+great attention for their promising light-matter applications. However, the
+excitation of a surface plasmon, in particular, transverse-electric (TE)
+surface plasmon, remains an outstanding challenge due to the difficulty to
+conserve energy and momentum simultaneously in the normal 2D materials. Here we
+show that the TE surface plasmons ranging from gigahertz to terahertz regime
+can be effectively excited and manipulated in a hybrid dielectric, 2D material
+and magnet structure. The essential physics is that the surface spin wave
+supplements an additional freedom of surface plasmon excitation and thus
+greatly enhances the electric field in the 2D medium. Based on widely-used
+magnetic materials like yttrium iron garnet (YIG) and manganese difluoride
+($\mathrm{MnF}_2$), we further show that the plasmon excitation manifests
+itself as a measurable dip in the reflection spectrum of the hybrid system
+while the dip position and the dip depth can be well controlled by the electric
+gating on the 2D layer and an external magnetic field. Our findings should
+bridge the fields of low-dimensional physics, plasmonics and spintronics and
+open a novel route to integrate plasmonic and spintronic devices.",2402.04626v1
+2024-03-23,Spatial Control of Hybridization-Induced Spin-Wave Transmission Stop Band,"Spin-wave (SW) propagation close to the hybridization-induced transmission
+stop band is investigated within a trapezoid-shaped 200\,nm thick yttrium iron
+garnet (YIG) film using time-resolved magneto-optic Kerr effect (TR-MOKE)
+microscopy and broadband spin wave spectroscopy, supported by micromagnetic
+simulations. The gradual reduction of the effective field within the structure
+leads to local variations of the SW dispersion relation and results in a SW
+hybridization at a fixed position in the trapezoid where the propagation
+vanishes since the SW group velocity approaches zero. By tuning external field
+or frequency, spatial control of the spatial stop band position and spin-wave
+propagation is demonstrated and utilized to gain transmission control over
+several microstrip lines.",2403.15840v1
+2001-04-30,Measurement of the Relativistic Potential Difference Across a Rotating Dielectric Cylinder,"According to the Special Theory of Relativity, a rotating magnetic dielectric
+cylinder in an axial magnetic field should exhibit a contribution to the radial
+electric potential that is associated with the motion of the material's
+magnetic dipoles. In 1913 Wilson and Wilson reported a measurement of the
+potential difference across a magnetic dielectric constructed from wax and
+steel balls. Their measurement has long been regarded as a verification of this
+prediction. In 1995 Pelligrini and Swift questioned the theoretical basis of
+experiment. In particular, they pointed out that it is not obvious that a
+rotating medium may be treated as if each point in the medium is locally
+inertial. They calculated the effect in the rotating frame and predicted a
+potential different from both Wilson's theory and experiment. Subsequent
+analysis of the experiment suggests that Wilson's experiment does not
+distinguish between the two predictions due to the fact that their composite
+steel-wax cylinder is conductive in the regions of magnetization. We report
+measurements of the radial voltage difference across various rotating
+dielectric cylinders, including a homogeneous magnetic material (YIG), to
+unambiguously test the competing calculations. Our results are compatible with
+the traditional treatment of the effect using a co-moving locally inertial
+reference frame, and are incompatible with the predictions based on the model
+of Pelligrini and Swift.",0104101v1
+2013-06-04,Determination of the origin of the spin Seebeck effect - bulk vs. interface effects,"The observation of the spin Seebeck effect in insulators has meant a
+breakthrough for spin caloritronics due to the unique ability to generate pure
+spin currents by thermal excitations in insulating systems without moving
+charge carriers. Since the recent first observation, the underlying mechanism
+and the origin of the observed signals have been discussed highly
+controversially. Here we present a characteristic dependence of the
+longitudinal spin Seebeck effect amplitude on the thickness of the insulating
+ferromagnet (YIG). Our measurements show that the observed behavior cannot be
+explained by any effects originating from the interface, such as magnetic
+proximity effects in the spin detector (Pt). Comparison to theoretical
+calculations of thermal magnonic spin currents yields qualitative agreement for
+the thickness dependence resulting from the finite effective magnon propagation
+length so that the origin of the effect can be traced to genuine bulk magnonic
+spin currents ruling out parasitic interface effects.",1306.0784v1
+2015-02-15,Redefinition of spin Hall magnetoresistance,"Using a multi-conduction-channel model, we redefined the micromechanism of
+spin Hall magnetoresistance (SMR). Four conduction channels are created by spin
+accumulation of nonpolarized electron flow at top, bottom, left and right
+interfaces of the film sample, which corresponds to different resistance states
+of polarized electron flow with various spin directions relative to the applied
+magnetic field ($\mathbf{H}$), and brings about the SMR effect finally. The
+magnetic insulator layer, such as yttrium iron garnet (YIG), is not a requisite
+for the observation of SMR. Instead, the SMR effect is perfectly realized, with
+an order of magnitude increase, in the sample with a discontinuous layer of
+isolated-Co$_2$FeAl (0.3 nm) grains covered by 2.5-nm-thick Pt layer on MgO
+substrate. The model intuitively gives the typical relationship of SMR effect,
+i.e. $\rho_{\parallel}\approx\rho_{\bot}>\rho_{T}$, where $\rho_{\bot}$,
+$\rho_{\parallel}$ and $\rho_{T}$ are longitudinal reisitivities with applied
+magnetic field ($\mathbf{H}$) direction perpendicular to the current direction
+out of plane (as Z direction), parallel with and perpendicular to it in plane
+(as X and Y direction), respectively. Our research reveals that the scattering
+between polarized and nonpolarized conduction electrons is the origin of SMR,
+and the intrinsic SMR is not constant when $\mathbf{H}$ direction rotates in XZ
+plane, which is distinct from that in the reported SMR mechanism.",1502.04288v1
+2016-01-08,Magnons and Phonons Optically Driven Out of Local Equilibrium in a Magnetic Insulator,"Magnons are the energy quanta of fundamental spin excitations, namely spin
+waves, and they can make a considerable contribution to energy transport in
+some magnetic materials in a similar manner as lattice vibration waves or
+phonons. The coupling and possible non-equilibrium between magnons and other
+energy carriers have been used to explain several recently discovered thermally
+driven spin transport and energy conversion phenomena. Here, we report
+experiments in which local non-equilibrium between magnons and phonons in a
+single crystalline bulk magnetic insulator, Y3Fe5O12 (yttrium iron garnet, or
+YIG), has been created optically within a focused laser spot and probed
+directly with the use of micro-Brillouin light scattering (BLS). By analyzing
+the experimental results with a thermally induced magnon diffusion model, we
+obtain the magnon diffusion length of thermal magnons. By explicitly
+establishing non-equilibrium between magnons and phonons, our studies represent
+an important step toward a quantitative understanding of various spin-heat
+coupling phenomena.",1601.01982v3
+2017-01-12,Longitudinal spin Seebeck coefficient: heat flux vs. temperature difference method,"The determination of the longitudinal spin Seebeck effect (LSSE) coefficient
+is currently plagued by a large uncertainty due to the poor reproducibility of
+the experimental conditions used in its measurement. In this work we present a
+detailed analysis of two different methods used for the determination of the
+LSSE coefficient. We have performed LSSE experiments in different laboratories,
+by using different setups and employing both the temperature difference method
+and the heat flux method. We found that the lack of reproducibility can be
+mainly attributed to the thermal contact resistance between the sample and the
+thermal baths which generate the temperature gradient. Due to the variation of
+the thermal resistance, we found that the scaling of the LSSE voltage to the
+heat flux through the sample rather than to the temperature difference across
+the sample greatly reduces the uncertainty. The characteristics of a single
+YIG/Pt LSSE device obtained with two different setups was $(1.143\pm0.007)\cdot
+10^{-7}$ Vm/W and $(1.101\pm0.015)\cdot 10^{-7}$ Vm/W with the heat flux method
+and $(2.313\pm0.017)\cdot 10^{-7}$ V/K and $(4.956\pm0.005)\cdot 10^{-7}$ V/K
+with the temperature difference method. This shows that systematic errors can
+be considerably reduced with the heat flux method.",1701.03285v3
+2017-09-06,Complex THz and DC inverse spin Hall effect in YIG/Cu$_{1-x}$Ir$_{x}$ bilayers across a wide concentration range,"We measure the inverse spin Hall effect of Cu$_{1-x}$Ir$_{x}$ thin films on
+yttrium iron garnet over a wide range of Ir concentrations ($0.05 \leqslant x
+\leqslant 0.7$). Spin currents are triggered through the spin Seebeck effect,
+either by a DC temperature gradient or by ultrafast optical heating of the
+metal layer. The spin Hall current is detected by, respectively, electrical
+contacts or measurement of the emitted THz radiation. With both approaches, we
+reveal the same Ir concentration dependence that follows a novel complex,
+non-monotonous behavior as compared to previous studies. For small Ir
+concentrations a signal minimum is observed, while a pronounced maximum appears
+near the equiatomic composition. We identify this behavior as originating from
+the interplay of different spin Hall mechanisms as well as a
+concentration-dependent variation of the integrated spin current density in
+Cu$_{1-x}$Ir$_{x}$. The coinciding results obtained for DC and ultrafast
+stimuli show that the studied material allows for efficient spin-to-charge
+conversion even on ultrafast timescales, thus enabling a transfer of
+established spintronic measurement schemes into the terahertz regime.",1709.01890v1
+2018-10-05,Magnon contribution to unidirectional spin Hall magnetoresistance,"We develop a model for the magnonic contribution to the unidirectional spin
+Hall magnetoresistance (USMR) of heavy metal/ferromagnetic insulator bilayer
+films. We show that diffusive transport of Holstein-Primakoff magnons leads to
+an accumulation of spin near the bilayer interface, giving rise to a
+magnoresistance which is not invariant under inversion of the current
+direction. Unlike the electronic contribution described by Zhang and Vignale
+[Phys. Rev. B 94, 140411 (2016)], which requires an electrically conductive
+ferromagnet, the magnonic contribution can occur in ferromagnetic insulators
+such as yttrium iron garnet. We show that the magnonic USMR is, to leading
+order, cubic in the spin Hall angle of the heavy metal, as opposed to the
+linear relation found for the electronic contribution. We estimate that the
+maximal magnonic USMR in Pt|YIG bilayers is on the order of $10^{-8}$, but may
+reach values of up to $10^{-5}$ if the magnon gap is suppressed, and can thus
+become comparable to the electronic contribution in, e.g., Pt|Co. We show that
+the magnonic USMR at a finite magnon gap may be enhanced by an order of
+magnitude if the magnon diffusion length is decreased to a specific optimal
+value that depends on various system parameters.",1810.02610v2
+2018-10-16,Spin-torque oscillation in a magnetic insulator probed by a single-spin sensor,"Coherent, self-sustained oscillation of magnetization in spin-torque
+oscillators (STOs) is a promising source for on-chip, nanoscale generation of
+microwave magnetic fields. Such fields could be used for local excitation of
+spin-wave resonances, control of spin qubits, and studies of paramagnetic
+resonance. However, local characterization of fields emitted by an STO has
+remained an outstanding challenge. Here, we use the spin of a single
+nitrogen-vacancy (NV) defect in diamond to probe the magnetic fields generated
+by an STO in a microbar of ferromagnetic insulator yttrium-iron-garnet (YIG).
+The combined spectral resolution and sensitivity of the NV sensor allows us to
+resolve multiple spin-wave modes and characterize their damping. When damping
+is decreased sufficiently via spin injection, the modes auto-oscillate, as
+indicated by a strongly reduced linewidth, a diverging magnetic power spectral
+density, and synchronization of the STO frequency to an external microwave
+source. These results open the way for quantitative, nanoscale mapping of the
+microwave signals generated by STOs, as well as harnessing STOs as local probes
+of mesoscopic spin systems.",1810.07306v1
+2018-11-02,Evidence for exchange Dirac gap in magneto-transport of topological insulator-magnetic insulator heterostructures,"Transport signatures of exchange gap opening because of magnetic proximity
+effect (MPE) are reported for bilayer structures of Bi2Se3 thin films on
+yttrium iron garnet (YIG) and thulium iron garnet (TmIG) of perpendicular
+magnetic anisotropy (PMA). Pronounced negative magnetoresistance (MR) was
+detected, and attributed to an emergent weak localization (WL) effect
+superimposing on a weak antilocalization (WAL). Thickness-dependent study shows
+that the WL originates from the time-reversal-symmetry breaking of topological
+surface states by interfacial exchange coupling. The weight of WL declined when
+the interfacial magnetization was aligned toward the in-plane direction, which
+is understood as the effect of tuning the exchange gap size by varying the
+perpendicular magnetization component. Importantly, magnetotransport study
+revealed anomalous Hall effect (AHE) of square loops and anisotropic
+magnetoresistance (AMR) characteristic, typifying a ferromagnetic conductor in
+Bi2Se3/TmIG, and the presence of an interfacial ferromagnetism driven by MPE.
+Coexistence of MPE-induced ferromagnetism and the finite exchange gap provides
+an opportunity of realizing zero magnetic-field dissipation-less transport in
+topological insulator/ferromagnetic insulator heterostructures.",1811.00689v1
+2019-01-28,Spin Hall magnetoresistance in heterostructures consisting of noncrystalline paramagnetic YIG and Pt,"The spin Hall magnetoresistance (SMR) effect arises from spin-transfer
+processes across the interface between a spin Hall active metal and an
+insulating magnet. While the SMR response of ferrimagnetic and
+antiferromagnetic insulators has been studied extensively, the SMR of a
+paramagnetic spin ensemble is not well established. Thus, we investigate herein
+the magnetoresistive response of as-deposited yttrium iron garnet/platinum thin
+film bilayers as a function of the orientation and the amplitude of an
+externally applied magnetic field. Structural and magnetic characterization
+show no evidence for crystalline order or spontaneous magnetization in the
+yttrium iron garnet layer. Nevertheless, we observe a clear magnetoresistance
+response with a dependence on the magnetic field orientation characteristic for
+the SMR. We propose two models for the origin of the SMR response in
+paramagnetic insulator/Pt heterostructures. The first model describes the SMR
+of an ensemble of non-interacting paramagnetic moments, while the second model
+describes the magnetoresistance arising by considering the total net moment.
+Interestingly, our experimental data are consistently described by the net
+moment picture, in contrast to the situation in compensated ferrimagnets or
+antiferromagnets.",1901.09986v1
+2019-03-05,All-optical cryogenic thermometry based on NV centers in nanodiamonds,"The nitrogen-vacancy (NV) center in diamond has been recognized as a
+high-sensitivity nanometer-scale metrology platform. Thermometry has been a
+recent focus, with attention largely confined to room temperature applications.
+Thermometry has been a recent focus, with attention largely confined to room
+temperature applications. Temperature sensing at low temperatures, however,
+remains challenging as the sensitivity decreases for many commonly used
+techniques which rely on a temperature dependent frequency shift of the NV
+centers spin resonance and its control with microwaves. Here we use an
+alternative approach that does not require microwaves, ratiometric all-optical
+thermometry, and demonstrate that it may be utilized to liquid nitrogen
+temperatures without deterioration of the sensitivity. The use of an array of
+nanodiamonds embedded within a portably polydimethylsiloxane (PDMS) sheet
+provides a versatile temperature sensing platform that can probe a wide variety
+of systems without the configurational restrictions needed for applying
+microwaves. With this device, we observe a temperature gradient over tens of
+microns in a ferromagnetic-insulator substrate (YIG) under local heating by a
+resistive heater. This thermometry technique provides a cryogenically
+compatible, microwave-free, minimally invasive approach capable of probing
+local temperatures with few restrictions on the substrate materials.",1903.01605v1
+2019-03-10,Magnons at low excitations: Observation of incoherent coupling to a bath of two-level-systems,"Collective magnetic excitation modes, magnons, can be coherently coupled to
+microwave photons in the single excitation limit. This allows for access to
+quantum properties of magnons and opens up a range of applications in quantum
+information processing, with the intrinsic magnon linewidth representing the
+coherence time of a quantum resonator. Our measurement system consists of a
+yttrium iron garnet (YIG) sphere and a three-dimensional (3D) microwave cavity
+at temperatures and excitation powers typical for superconducting quantum
+circuit experiments. We perform spectroscopic measurements to determine the
+limiting factor of magnon coherence at these experimental conditions. Using the
+input-output formalism, we extract the magnon linewidth $\kappa_\mathrm{m}$. We
+attribute the limitations of the coherence time at lowest temperatures and
+excitation powers to incoherent losses into a bath of near-resonance two-level
+systems (TLSs), a generic loss mechanism known from superconducting circuits
+under these experimental conditions. We find that the TLSs saturate when
+increasing the excitation power from quantum excitation to multi-photon
+excitation and their contribution to the linewidth vanishes. At higher
+temperatures, the TLSs saturate thermally and the magnon linewidth decreases as
+well.",1903.03981v3
+2019-03-22,Effects of post-deposition annealing on the structure and magnetization of PLD grown Yttrium Iron Garnet films,"We report on the recrystallization of 200 nm thick as-grown Yttrium Iron
+Garnet (Y_3.4 Fe_4.6 O_12) films on (111) face of Gadolinium Gallium Garnet
+(GGG) single crystals by post-deposition annealing. Epitaxial conversion of the
+as-grown microcrystalline YIG films was seen after annealing at 800oC for more
+than 30 minutes both in ambient oxygen as well as in air. The as-grown oxygen
+annealed samples at 800oC for 60 minutes crystallize epitaxially and show
+excellent figure-of-merit for saturation magnetization (MS = 3.3 {\mu}B/f.u.,
+comparable to bulk value) and coercivity (HC ~ 1.1 Oe). The ambient air
+annealing at 800oC with a very slow rate of cooling (2oC/min) results in a
+double layer structure with a thicker unstrained epitaxial top layer having the
+MS and HC of 2.9 {\mu}B/f.u. and 0.12 Oe respectively. The symmetric and
+asymmetric Reciprocal space maps of both the samples reveal a locking of the
+in-plane lattice of the film to the in-plane lattice of substrate, indicating a
+pseudomorphic growth. The residual stress calculated by sin^2 {\psi} technique
+is compressive in nature. The lower layer in air annealed sample is highly
+strained, whereas, the top layer has negligible compressive stress.",1903.09457v1
+2019-05-17,High-efficiency triple-resonant inelastic light scattering in planar optomagnonic cavities,"Optomagnonic cavities have recently been emerging as promising candidates for
+implementing coherent microwave-to-optical conversion, quantum memories and
+devices, and next generation quantum networks. A key challenge in the design of
+such cavities is the attainment of high efficiencies, which could, e.g., be
+exploited for efficient optical interfacing of superconducting qubits, as well
+as the practicality of the final designs, which ideally should be planar and
+amenable to on-chip integration. Here, on the basis of a novel time Floquet
+scattering-matrix approach, we report on the design and optimization of a
+planar, multilayer optomagnonic cavity, incorporating a Ce:YIG thin film,
+magnetized in-plane, operating in the triple-resonant inelastic light
+scattering regime. This architecture allows for conversion efficiencies of
+about 5%, under realistic conditions, which is orders of magnitude higher than
+alternative designs. Our results suggest a viable way forward for realizing
+practical information inter-conversion between microwave photons and optical
+photons, mediated by magnons, with efficiencies intrinsically greater than
+those achieved in optomechanics and alternative related technologies, as well
+as a platform for fundamental studies of classical and quantum dynamics in
+magnetic solids, and implementation of futuristic quantum devices.",1905.07278v1
+2019-11-01,Role of spin mixing conductance in determining thermal spin pumping near the ferromagnetic phase transition in EuO_{1-x} and La2NiMnO6,"We present a comprehensive study of the temperature (T) dependence of the
+longitudinal spin Seebeck effect (LSSE) in Pt/EuO_{1-x} and Pt/La2NiMnO6 (LNMO)
+hybrid structures across their Curie temperatures (Tc). Both systems host
+ferromagnetic interaction below Tc, hence present optimal conditions for
+testing magnon spin current based theories against ferrimagnetic YIG. Notably,
+we observe an anomalous Nernst effect (ANE) generated voltage in bare
+EuO_{1-x}, however, we find LSSE predominates the thermal signals in the
+bilayers with Pt. The T-dependence of the LSSE in small T-range near Tc could
+be fitted to a power law of the form (Tc-T)^P. The derived critical exponent,
+P, was verified for different methods of LSSE representation and sample
+crystallinity. The results are explained based on the magnon-driven thermal
+spin pumping mechanism that relate the T-dependence of LSSE to the spin mixing
+conductance (Gmix) at the heavy metal/ferromagnet (HM/FM) interface, which in
+turn is known to vary in accordance with the square of the spontaneous
+magnetization (Ms). Additionally, the T-dependence of the real part of Gmix
+derived from spin Hall magnetoresistance measurements at different temperatures
+for the Pt/LNMO structure, further establish the interdependence.",1911.00211v1
+2020-01-24,Axion search with a quantum-limited ferromagnetic haloscope,"A ferromagnetic axion haloscope searches for Dark Matter in the form of
+axions by exploiting their interaction with electronic spins. It is composed of
+an axion-to-electromagnetic field transducer coupled to a sensitive rf
+detector. The former is a photon-magnon hybrid system, and the latter is based
+on a quantum-limited Josephson parametric amplifier. The hybrid system consists
+of ten 2.1 mm diameter YIG spheres coupled to a single microwave cavity mode by
+means of a static magnetic field. Our setup is the most sensitive rf
+spin-magnetometer ever realized. The minimum detectable field is
+$5.5\times10^{-19}\,$T with 9 h integration time, corresponding to a limit on
+the axion-electron coupling constant $g_{aee}\le1.7\times10^{-11}$ at 95% CL.
+The scientific run of our haloscope resulted in the best limit on DM-axions to
+electron coupling constant in a frequency span of about 120 MHz, corresponding
+to the axion mass range $42.4$-$43.1\,\mu$eV. This is also the first apparatus
+to perform an axion mass scanning by changing the static magnetic field.",2001.08940v1
+2020-01-31,Temperature dependence of spin pinning and spin-wave dispersion in nanoscopic ferromagnetic waveguides,"The field of magnonics attracts significant attention due to the possibility
+of utilizing information coded into the spin-wave phase or amplitude to perform
+computation operations on the nanoscale. Recently, spin waves were investigated
+in Yttrium Iron Garnet (YIG) waveguides with widths ranging down to 50 nm and
+aspect ratios thickness over width approaching unity. A critical width was
+found, below which the exchange interaction suppresses the dipolar pinning
+phenomenon and the system becomes unpinned. Here we continue these
+investigations and analyse the pinning phenomenon and spin-wave dispersions as
+a function of temperature, thickness and material of choice. Higher order
+modes, the influence of a finite wavevector along the waveguide and the impact
+of the pinning phenomenon on the spin-wave lifetime are discussed as well as
+the influence of a trapezoidal cross section and edge roughness of the
+waveguides. The presented results are of particular interest for potential
+applications in magnonic devices and the incipient field of quantum magnonics
+at cryogenic temperatures.",2002.00003v1
+2020-04-16,A Magnon Scattering Platform,"Scattering experiments have revolutionized our understanding of nature.
+Examples include the discovery of the nucleus, crystallography, and the
+discovery of the double helix structure of DNA. Scattering techniques differ by
+the type of the particles used, the interaction these particles have with
+target materials and the range of wavelengths used. Here, we demonstrate a new
+2-dimensional table-top scattering platform for exploring magnetic properties
+of materials on mesoscopic length scales. Long lived, coherent magnonic
+excitations are generated in a thin film of YIG and scattered off a magnetic
+target deposited on its surface. The scattered waves are then recorded using a
+scanning NV center magnetometer that allows sub-wavelength imaging and
+operation under conditions ranging from cryogenic to ambient environment. While
+most scattering platforms measure only the intensity of the scattered waves,
+our imaging method allows for spatial determination of both amplitude and phase
+of the scattered waves thereby allowing for a systematic reconstruction of the
+target scattering potential. Our experimental results are consistent with
+theoretical predictions for such a geometry and reveal several unusual features
+of the magnetic response of the target, including suppression near the target
+edges and gradient in the direction perpendicular to the direction of surface
+wave propagation. Our results establish magnon scattering experiments as a new
+platform for studying correlated many-body systems.",2004.07763v1
+2020-05-18,The Einstein - de Haas effect at radio frequencies in and near magnetic equilibrium,"The Einstein-de Haas (EdH) effect and its reciprocal the Barnett effect are
+fundamental to magnetism and uniquely yield measures of the ratio of magnetic
+moment to total angular momentum. These effects, small and generally difficult
+to observe, are enjoying a resurgence of interest as contemporary techniques
+enable new approaches to their study. The high mechanical resonance frequencies
+in nanomechanical systems offer a tremendous advantage for the observation of
+EdH torques in particular. At radio frequencies, the EdH effect can become
+comparable to or even exceed in magnitude conventional cross-product magnetic
+torques. In addition, the RF-EdH torque is expected to be phase-shifted by 90
+degrees relative to cross-product torques, provided the magnetic system remains
+in quasi-static equilibrium, enabling separation in quadratures when both
+sources of torque are operative. Radio frequency EdH measurements are
+demonstrated through the full hysteresis range of micrometer scale,
+monocrystalline yttrium iron garnet (YIG) disks. Equilibrium behavior is
+observed in the vortex state at low bias field. Barkhausen-like features emerge
+in the in-plane EdH torque at higher fields in the vortex state, revealing
+magnetic disorder too weak to be visible through the in-plane cross-product
+torque. Beyond vortex annihilation, peaks arise in the EdH torque versus bias
+field, and these together with their phase signatures indicate additional
+utility of the Einstein-de Haas effect for the study of RF-driven spin
+dynamics.",2005.08406v1
+2020-07-17,Coherent coupling between multiple ferrimagnetic spheres and a microwave cavity in the quantum-limit,"The spin resonance of electrons can be coupled to a microwave cavity mode to
+obtain a photon-magnon hybrid system. These quantum systems are widely studied
+for both fundamental physics and technological quantum applications. In this
+article, the behavior of a large number of ferrimagnetic spheres coupled to a
+single cavity is put under test. We use second-quantization modeling of
+harmonic oscillators to theoretically describe our experimental setup and
+understand the influence of several parameters. The magnon-polariton dispersion
+relation is used to characterize the system, with a particular focus on the
+vacuum Rabi mode splitting due to multiple spheres. We combine the results
+obtained with simple hybrid systems to analyze the behavior of a more complex
+one, and show that it can be devised in such a way to minimize the degrees of
+freedom needed to completely describe it. By studying single-sphere coupling
+two possible size-effects related to the sample diameter have been identified,
+while multiple-spheres configurations reveal how to upscale the system. This
+characterization is useful for the implementation of an
+axion-to-electromagnetic field transducer in a ferromagnetic haloscope for dark
+matter searches. Our dedicated setup, consisting in ten 2 mm-diameter YIG
+spheres coupled to a copper microwave cavity, is used for this aim and studied
+at mK temperatures. Moreover, we show that novel applications of
+optimally-controlled hybrid systems can be foreseen for setups embedding a
+large number of samples.",2007.08908v3
+2021-02-26,Control of the Bose-Einstein Condensation of Magnons by the Spin-Hall Effect,"Previously, it has been shown that rapid cooling of yttrium-iron-garnet
+(YIG)/platinum (Pt) nano structures, preheated by an electric current sent
+through the Pt layer, leads to overpopulation of a magnon gas and to subsequent
+formation of a Bose-Einstein condensate (BEC) of magnons. The spin Hall effect
+(SHE), which creates a spin-polarized current in the Pt layer, can inject or
+annihilate magnons depending on the electric current and applied field
+orientations. Here we demonstrate that the injection or annihilation of magnons
+via the SHE can prevent or promote the formation of a rapid cooling induced
+magnon BEC. Depending on the current polarity, a change in the BEC threshold of
+-8% and +6% was detected. These findings demonstrate a new method to control
+macroscopic quantum states, paving the way for their application in spintronic
+devices.",2102.13481v2
+2021-07-14,Sublattice spin reversal and field induced $Fe^{3+}$ spin-canting across the magnetic compensation temperature in $Y_{1.5}Gd_{1.5}Fe_{5}O_{12}$ rare-earth iron garnet,"In the present work $Fe^{3+}$ sublattice spin reversal and $Fe^{3+}$
+spin-canting across the magnetic compensation temperature ($T_{Comp}$) are
+demonstrated in polycrystalline $Y_{1.5}Gd_{1.5}Fe_{5}O_{12}$ (YGdIG) by means
+of in-field $^{57}Fe$ M$\ddot{o}$ssbauer spectroscopy measurements.
+Corroborating in-field $^{57}Fe$ M$\ddot{o}$ssbauer measurements, both
+$Fe^{3+}$ & $Gd^{3+}$ sublattice spin reversal has also been manifested with
+x-ray magnetic circular dichroism (XMCD) measurement in hard x-ray region.
+Moreover from in-field $^{57}Fe$ M$\ddot{o}$ssbauer measurements, estimation
+and analysis of effective internal hyperfine field ($H_{eff}$), relative
+intensity of absorption lines in a sextet elucidated unambiguously the
+signatures of $Fe^{3+}$ spin reversal, their continuous transition and field
+induced spin-canting of $Fe^{3+}$ sublattices across $T_{Comp}$. Further, Fe K-
+(Gd $L_{3}$-) edge XMCD signal is observed to consist of additional spectral
+features, those are identified from $Gd^{3+}$ ($Fe^{3+}$) magnetic ordering,
+enabling us the extraction of both the sublattices ($Fe^{3+}$ & $Gd^{3+}$)
+information from a single edge analysis. The evolution of the magnetic moments
+as a function of temperature for both magnetic sublattices extracted either at
+the Fe K- or Gd $L_3$-edge agree quite well with values that are extracted from
+bulk magnetization data of YGdIG and YIG ($Y_{3}Fe_{5}O_{12}$). These
+measurements pave new avenues to investigate how the magnetic behavior of such
+complex system acts across the compensation point.",2107.06508v3
+2021-07-20,Spin-wave dispersion measurement by variable-gap propagating spin-wave spectroscopy,"Magnonics is seen nowadays as a candidate technology for energy-efficient
+data processing in classical and quantum systems. Pronounced nonlinearity,
+anisotropy of dispersion relations and phase degree of freedom of spin waves
+require advanced methodology for probing spin waves at room as well as at mK
+temperatures. Yet, the use of the established optical techniques like Brillouin
+light scattering (BLS) or magneto optical Kerr effect (MOKE) at ultra-low
+temperatures is forbiddingly complicated. By contrast, microwave spectroscopy
+can be used at all temperatures but is usually lacking spatial and wavenumber
+resolution. Here, we develop a variable-gap propagating spin-wave spectroscopy
+(VG-PSWS) method for the deduction of the dispersion relation of spin waves in
+wide frequency and wavenumber range. The method is based on the phase-resolved
+analysis of the spin-wave transmission between two antennas with variable
+spacing, in conjunction with theoretical data treatment. We validate the method
+for the in-plane magnetized CoFeB and YIG thin films in $k\perp B$ and
+$k\parallel B$ geometries by deducing the full set of material and spin-wave
+parameters, including spin-wave dispersion, hybridization of the fundamental
+mode with the higher-order perpendicular standing spin-wave modes and surface
+spin pinning. The compatibility of microwaves with low temperatures makes this
+approach attractive for cryogenic magnonics at the nanoscale.",2107.09363v1
+2021-08-02,Circular displacement current induced anomalous magneto-optical effects in high index Mie resonators,"Dielectric Mie nanoresonators showing strong light-matter interaction at the
+nanoscale may enable new functionality in photonic devices. Recently, strong
+magneto-optical effects have been observed in magneto-optical nanophotonic
+devices due to the electromagnetic field localization. However, most reports so
+far have been focused on the enhancement of conventional magneto-optical
+effects. Here, we report the observation of circular displacement current
+induced anomalous magneto-optical effects in high-index-contrast
+Si/Ce:YIG/YIG/SiO2 Mie resonators. In particular, giant modulation of light
+intensity in transverse magnetic configuration up to 6.4 % under s-polarized
+incidence appears, which is non-existent in planar magneto-optical thin films.
+Apart from that, we observe a large rotation of transmitted light polarization
+in the longitudinal magnetic configuration under near normal incidence
+conditions, which is two orders of magnitude higher than for a planar
+magneto-optical thin film. These phenomena are essentially originated from the
+unique circular displacement current when exciting the magnetic resonance modes
+in the Mie resonators, which changes the incident electric field direction
+locally. Our work indicates an uncharted territory of light polarization
+control based on the complex modal profiles in all-dielectric magneto-optical
+Mie resonators and metasurfaces, which opens the door for versatile control of
+light propagation by magnetization for a variety of applications in vectoral
+magnetic field and biosensing, free space non-reciprocal photonic devices,
+magneto-optical imaging and optomagnetic memories.",2108.00615v1
+2021-07-14,Broadband energy squeezing and tunneling based on unidirectional modes,"Energy squeezing attracts many attentions for its potential applications in
+electromagnetic (EM) energy harvesting and optical communication. However, due
+to the Fabry-Perot resonance, only the EM waves with discrete frequencies can
+be squeezed and, as far as we know, in the previous energy-squeezing devices,
+stringent requirements of the materials or the geometrical shape are needed. We
+note that the structures filled with epsilon-near-zero (ENZ) mediums as
+reported in some works can squeeze and tunnel EM waves at frequencies (e.g.
+plasma frequency). However, the group velocity is usually near zero which means
+few EM information travel through the structures. In this paper, low-loss
+energy squeezing and tunneling (EST) based on unidirectional modes were
+demonstrated in YIG-based one-way waveguides at microwave frequencies.
+According to our theoretical analysis and the simulations using finite element
+method, broadband EST was achieved and the EM EST was observed even for
+extremely bended structures. Besides, similar EM EST was achieved in a
+realistic three-dimensional remanence-based one-way waveguide as well. The
+unidirectional modes-based EST paving the way to ultra-subwavelength EM
+focusing, enhanced nonlinear optics, and designing numerous functional devices
+in integrated optical circuits such as phase modulator.",2108.04196v1
+2022-01-23,Squeezed driving induced entanglement and squeezing among cavity modes and magnon mode in a magnon-cavity QED system,"We propose a scheme to generate entanglement between two cavity modes and
+squeeze magnon mode in a magnon-cavity QED system, where the two microwave
+cavity modes are coupled with a massive yttrium iron garnet (YIG) sphere
+through magnetic dipole interaction. The nonlinearity used in our system
+originates from a squeezed driving via parametric down-conversion process,
+which is the reason to cause entanglement and squeezing. By using the mean
+field approximation and employing experimentally feasible parameters, we
+demonstrate that the system shows zero entanglement and squeezing without
+squeezed driving. Meanwhile, our QED system denotes that the entanglement
+between squeezed cavity mode and magnon mode can be transferred to the other
+cavity mode and magnon mode via magnon-cavity coupling interaction, and then
+the two cavity modes get entangled. A genuinely tripartite entangled state is
+formed. We also show that magnon mode can be prepared in a squeezed state via
+magnon-cavity beam-splitter interaction, which is as a result of the squeezed
+field. Moreover, we show that it is a good way to enhance entanglement and
+squeezing by increasing the nonlinear gain coefficient of squeezed driving. Our
+results denote that magnon-cavity QED system is a powerful platform for
+studying macroscopic quantum phenomena, which illustrates a new method to
+photon-photon entanglement and magnon squeezing.",2201.09154v1
+2022-03-12,Observation of nonlinear planar Hall effect in magnetic insulator/topological insulator heterostructures,"Interfacing topological insulators (TIs) with magnetic insulators (MIs) has
+been widely used to study the interaction between topological surface states
+and magnetism. Previous transport studies typically interpret the suppression
+of weak antilocalization or appearance of the anomalous Hall effect as
+signatures of magnetic proximity effect (MPE) imposed to TIs. Here, we report
+the observation of nonlinear planar Hall effect (NPHE) in Bi2Se3 films grown on
+MI thulium and yttrium iron garnet (TmIG and YIG) substrates, which is an order
+of magnitude larger than that in Bi2Se3 grown on nonmagnetic gadolinium gallium
+garnet (GGG) substrate. The nonlinear Hall resistance in TmIG/Bi2Se3 depends
+linearly on the external magnetic field, while that in YIG/Bi2Se3 exhibits an
+extra hysteresis loop around zero field. The magnitude of the NPHE is found to
+scale inversely with carrier density. We speculate the observed NPHE is related
+to the MPE-induced exchange gap opening and out-of-plane spin textures in the
+TI surface states, which may be used as an alternative transport signature of
+the MPE in MI/TI heterostructures.",2203.06293v2
+2023-01-13,Voltage-Controlled Magnon Transistor via Tunning Interfacial Exchange Coupling,"Magnon transistors that can effectively regulate magnon transport by an
+electric field are desired for magnonics which aims to provide a Joule-heating
+free alternative to the conventional electronics owing to the electric
+neutrality of magnons (the key carriers of spin-angular momenta in the
+magnonics). However, also due to their electric neutrality, magnons have no
+access to directly interact with an electric field and it is thus difficult to
+manipulate magnon transport by voltages straightforwardly. Here, we
+demonstrated a gate voltage ($V_{\rm g}$) applied on a nonmagnetic
+metal/magnetic insulator (NM/MI) interface that bended the energy band of the
+MI and then modulated the possibility for conduction electrons in the NM to
+tunnel into the MI can consequently enhance or weaken the spin-magnon
+conversion efficiency at the interface. A voltage-controlled magnon transistor
+based on the magnon-mediated electric current drag (MECD) effect in a
+Pt/Y$_{\rm 3}$Fe$_{\rm 5}$O$_{\rm 12}$ (YIG)/Pt sandwich was then
+experimentally realized with $V_{\rm g}$ modulating the magnitude of the MECD
+signal. The obtained efficiency (the change ratio between the MECD voltage at
+$\pm V_{\rm g}$) reached 10%/(MV/cm) at 300 K. This prototype of magnon
+transistor offers an effective scheme to control magnon transport by a gate
+voltage.",2301.05592v1
+2023-02-02,Leveraging symmetry for an accurate spin-orbit torques characterization in ferrimagnetic insulators,"Spin-orbit torques (SOTs) have emerged as an efficient means to electrically
+control the magnetization in ferromagnetic heterostructures. Lately, an
+increasing attention has been devoted to SOTs in heavy metal (HM)/magnetic
+insulator (MI) bilayers owing to their tunable magnetic properties and
+insulating nature. Quantitative characterization of SOTs in HM/MI
+heterostructures are, thus, vital for fundamental understanding of charge-spin
+interrelations and designing novel devices. However, the accurate determination
+of SOTs in MIs have been limited so far due to small electrical signal outputs
+and dominant spurious thermoelectric effects caused by Joule heating. Here, we
+report a simple methodology based on harmonic Hall voltage detection and
+macrospin simulations to accurately quantify the damping-like and field-like
+SOTs, and thermoelectric contributions separately in MI-based systems.
+Experiments on the archetypical Bi-doped YIG/Pt heterostructure using the
+developed method yield precise values for the field-like and damping-like SOTs,
+reaching -0.14 and -0.15 mT per 1.7x$10^{ 11}$ A/$m^2$, respectively. We
+further reveal that current-induced Joule heating changes the spin transparency
+at the interface, reducing the spin Hall magnetoresistance and damping-like
+SOT, simultaneously. These results and the devised method can be beneficial for
+fundamental understanding of SOTs in MI-based heterostructures and designing
+new devices where accurate knowledge of SOTs is necessary.",2302.01141v2
+2023-03-07,Magnon currents excited by the spin Seebeck effect in ferromagnetic EuS thin films,"A magnetic insulator is an ideal platform to propagate spin information by
+exploiting magnon currents. However, until now, most studies have focused on
+Y$_3$Fe$_5$O$_{12}$ (YIG) and a few other ferri- and antiferromagnetic
+insulators, but not on pure ferromagnets. In this study, we demonstrate for the
+first time that magnon currents can propagate in ferromagnetic insulating thin
+films of EuS. By performing both local and non-local transport measurements in
+18-nm-thick films of EuS using Pt electrodes, we detect magnon currents arising
+from thermal generation by the spin Seebeck effect. By comparing the dependence
+of the local and non-local signals with the temperature (< 30 K) and magnetic
+field (< 9 T), we confirm the magnon transport origin of the non-local signal.
+Finally, we extract the magnon diffusion length in the EuS film (~140 nm), a
+short value in good correspondence with the large Gilbert damping measured in
+the same film.",2303.03833v2
+2023-04-21,Magnon squeezing by two-tone driving of a qubit in cavity-magnon-qubit systems,"We propose a scheme for preparing magnon squeezed states in a hybrid
+cavity-magnon-qubit system. The system consists of a microwave cavity that
+simultaneously couples to a magnon mode of a macroscopic yttrium-iron-garnet
+(YIG) sphere via the magnetic-dipole interaction and to a transmon-type
+superconducting qubit via the electric-dipole interaction. By far detuning from
+the magnon-qubit system, the microwave cavity is adiabatically eliminated. The
+magnon mode and the qubit then get effectively coupled via the mediation of
+virtual photons of the microwave cavity. We show that by driving the qubit with
+two microwave fields and by appropriately choosing the drive frequencies and
+strengths, magnonic parametric amplification can be realized, which leads to
+magnon quadrature squeezing with the noise below vacuum fluctuation. We provide
+optimal conditions for achieving magnon squeezing, and moderate squeezing can
+be obtained using currently available parameters. The generated squeezed states
+are of a magnon mode involving more than $10^{18}$ spins and thus macroscopic
+quantum states. The work may find promising applications in quantum information
+processing and high-precision measurements based on magnons and in the study of
+macroscopic quantum states.",2304.10760v4
+2023-07-12,Quantum information diode based on a magnonic crystal,"Exploiting the effect of nonreciprocal magnons in a system with no inversion
+symmetry, we propose a concept of a quantum information diode, {\it i.e.}, a
+device rectifying the amount of quantum information transmitted in the opposite
+directions. We control the asymmetric left and right quantum information
+currents through an applied external electric field and quantify it through the
+left and right out-of-time-ordered correlation (OTOC). To enhance the
+efficiency of the quantum information diode, we utilize a magnonic crystal. We
+excite magnons of different frequencies and let them propagate in opposite
+directions. Nonreciprocal magnons propagating in opposite directions have
+different dispersion relations. Magnons propagating in one direction match
+resonant conditions and scatter on gate magnons. Therefore, magnon flux in one
+direction is damped in the magnonic crystal leading to an asymmetric transport
+of quantum information in the quantum information diode. A quantum information
+diode can be fabricated from an yttrium iron garnet (YIG) film. This is an
+experimentally feasible concept and implies certain conditions: low temperature
+and small deviation from the equilibrium to exclude effects of phonons and
+magnon interactions. We show that rectification of the flaw of quantum
+information can be controlled efficiently by an external electric field and
+magnetoelectric effects.",2307.06047v1
+2023-07-14,Magnonic Combinatorial Memory,"In this work, we consider a type of magnetic memory where information is
+encoded into the mutual arrangements of magnets. The device is an active ring
+circuit comprising magnetic and electronic parts connected in series. The
+electric part includes a broad-band amplifier, phase shifters, and attenuators.
+The magnetic part is a mesh of magnonic waveguides with magnets placed on the
+waveguide junctions. There are amplitude and phase conditions for
+auto-oscillations to occur in the active ring circuit. The frequency(s) of the
+auto-oscillation and spin wave propagation route(s) in the magnetic part
+depends on the mutual arrangement of magnets in the mesh. The propagation route
+is detected with a set of power sensors. The correlation between circuit
+parameters and spin wave route is the base of memory operation. The combination
+of input/output switches connecting electric and magnetic parts, and electric
+phase shifters constitute the memory address. The output of power sensors is
+the memory state. We present experimental data on the proof-of-the-concept
+experiments on the prototype with just three magnets placed on top of a
+single-crystal yttrium iron garnet Y3Fe2(FeO4)3 (YIG) film. The results
+demonstrate a robust operation with On/Off ratio for route detection exceeding
+35 dB at room temperature. The number of propagation routes scales factorial
+with the size of the magnetic part. Coding information in propagation routes
+makes it possible to drastically increase the data storage density compared to
+conventional memory devices. MCM with just 25 magnets can store as much as 25!
+(10 Yotta) bits. Physical limits and constraints are also discussed.",2307.07464v1
+2023-12-15,Magnon Bose-Einstein condensates: from time crystals and quantum chromodynamics to vortex sensing and cosmology,"Under suitable experimental conditions collective spin-wave excitations,
+magnons, form a Bose-Einstein condensate (BEC) where the spins precess with a
+globally coherent phase. Bose-Einstein condensation of magnons has been
+reported in a few systems, including superfluid phases of $^3$He, solid state
+systems such as Yttrium-iron-garnet (YIG) films, and cold atomic gases. Among
+these systems, the superfluid phases of $^3$He provide a nearly ideal test
+bench for coherent magnon physics owing to experimentally proven spin
+superfluidity, the long lifetime of the magnon condensate, and the versatility
+of the accessible phenomena. We first briefly recap the properties of the
+different magnon BEC systems, with focus on superfluid $^3$He. The main body of
+this review summarizes recent advances in application of magnon BEC as a
+laboratory to study basic physical phenomena connecting to diverse areas from
+particle physics and cosmology to new phases of condensed matter. This line of
+research complements the ongoing efforts to utilize magnon BECs as probes and
+components for potentially room-temperature quantum devices. In conclusion, we
+provide a roadmap for future directions in the field of applications of magnon
+BEC to fundamental research.",2312.10119v1
+2024-01-04,Nonreciprocal photon blockade with Kerr magnons,"Nonreciprocal devices, allowing to manipulate one-way signals, are crucial to
+quantum information processing and quantum network. Here we propose a nonlinear
+cavity-magnon system, consisting of a microwave cavity coupled to one or two
+yttrium-iron-garnet (YIG) spheres supporting magnons with Kerr nonlinearity, to
+investigate nonreciprocal photon blockade. The nonreciprocity originates from
+the direction-dependent Kerr effect, distinctly different from previous
+proposals with spinning cavities and dissipative couplings. For a single sphere
+case, nonreciprocal photon blockade can be realized by manipulating the
+nonreciprocal destructive interference between two active paths, via vary the
+Kerr coefficient from positive to negative, or vice versa. By optimizing the
+system parameters, the perfect and well tuned nonreciprocal photon blockade can
+be predicted. For the case of two spheres with opposite Kerr effects, only
+reciprocal photon blockade can be observed when two cavity-magnon coupling
+strengths Kerr strengths are symmetric. However, when coupling strengths or
+Kerr strengths become asymmetric, nonreciprocal photon blockade appears. This
+implies that two-sphere nonlinear cavity-magnon systems can be used to switch
+the transition between reciprocal and nonreciprocal photon blockades. Our study
+offers a potential platform for investigating nonreciprocal photon blockade
+effect in nonlinear cavity magnonics.",2401.02251v1
+2024-02-06,Magnon mediated spin pumping by coupled ferrimagnetic garnets heterostructure,"Spin pumping has significant implications for spintronics, providing a
+mechanism to manipulate and transport spins for information processing.
+Understanding and harnessing spin currents through spin pumping is critical for
+the development of efficient spintronic devices. The use of a magnetic
+insulator with low damping, enhances the signal-to-noise ratio in crucial
+experiments such as spin-torque ferromagnetic resonance (FMR) and spin pumping.
+A magnetic insulator coupled with a heavy metal or quantum material offers a
+more straight forward model system, especially when investigating spin-charge
+interconversion processes to greater accuracy. This simplicity arises from the
+absence of unwanted effects caused by conduction electrons unlike in
+ferromagnetic metals. Here, we investigate the spin pumping in coupled
+ferrimagnetic (FiM) Y3Fe5O12 (YIG)/Tm3Fe5O12 (TmIG) bilayers combined with
+heavy-metal (Pt) using the inverse spin Hall effect (ISHE). It is observed that
+magnon transmission occurs at both of the FiMs FMR positions. The enhancement
+of spin pumping voltage (Vsp) in the FiM garnet heterostructures is attributed
+to the strong interfacial exchange coupling between FiMs. The modulation of Vsp
+is achieved by tuning the bilayer structure. Further, the spin mixing
+conductance for these coupled systems is found to be 10^18 m^-2. Our findings
+describe a novel coupled FiM system for the investigation of magnon coupling
+providing new prospects for magnonic devices.",2402.03734v1
+2001-09-19,Solid State Systems for Electron Electric Dipole Moment and other Fundamental Measurements,"In 1968, F.L. Shapiro published the suggestion that one could search for an
+electron EDM by applying a strong electric field to a substance that has an
+unpaired electron spin; at low temperature, the EDM interaction would lead to a
+net sample magnetization that can be detected with a SQUID magnetometer. One
+experimental EDM search based on this technique was published, and for a number
+of reasons including high sample conductivity, high operating temperature, and
+limited SQUID technology, the result was not particularly sensitive compared to
+other experiments in the late 1970's.
+  Advances in SQUID and conventional magnetometery had led us to reconsider
+this type of experiment, which can be extended to searches and tests other than
+EDMs (e.g., test of Lorentz invariance). In addition, the complementary
+measurement of an EDM-induced sample electric polarization due to application
+of a magnetic field to a paramagnetic sample might be effective using modern
+ultrasensitive charge measurement techniques. A possible paramagnetic material
+is Gd-substituted YIG which has very low conductivity and a net enhancement
+(atomic enhancement times crystal screening) of order unity. Use of a
+reasonable volume (100's of cc) sample of this material at 50 mK and 10 kV/cm
+might yield an electron EDM sensitivity of $10^{-33}$ e cm or better, a factor
+of $10^6$ improvement over current experimental limits.",0109014v4
+2016-12-21,Bose-Einstein Condensation of Quasi-Particles by Rapid Cooling,"The fundamental phenomenon of Bose-Einstein Condensation (BEC) has been
+observed in different systems of real and quasi-particles. The condensation of
+real particles is achieved through a major reduction in temperature while for
+quasi-particles a mechanism of external injection of bosons by irradiation is
+required. Here, we present a novel and universal approach to enable BEC of
+quasi-particles and to corroborate it experimentally by using magnons as the
+Bose-particle model system. The critical point to this approach is the
+introduction of a disequilibrium of magnons with the phonon bath. After heating
+to an elevated temperature, a sudden decrease in the temperature of the
+phonons, which is approximately instant on the time scales of the magnon
+system, results in a large excess of incoherent magnons. The consequent
+spectral redistribution of these magnons triggers the Bose-Einstein
+condensation.",1612.07305v3
+2018-01-04,Complex temperature dependence of coupling and dissipation of cavity-magnon polaritons from milliKelvin to room temperature,"Hybridized magnonic-photonic systems are key components for future
+information processing technologies such as storage, manipulation or conversion
+of data both in the classical (mostly at room temperature) and quantum
+(cryogenic) regime. In this work, we investigate a YIG sphere coupled strongly
+to a microwave cavity over the full temperature range from $290\,\mathrm{K}$
+down to $30\,\mathrm{mK}$. The cavity-magnon polaritons are studied from the
+classical to the quantum regime where the thermal energy is less than one
+resonant microwave quanta, i.e. at temperatures below $1\,\mathrm{K}$. We
+compare the temperature dependence of the coupling strength $g_{\rm{eff}}(T)$,
+describing the strength of coherent energy exchange between spin ensemble and
+cavity photon, to the temperature behavior of the saturation magnetization
+evolution $M_{\rm{s}}(T)$ and find strong deviations at low temperatures. The
+temperature dependence of magnonic disspation is governed at intermediate
+temperatures by rare earth impurity scattering leading to a strong peak at
+$40\,$K. The linewidth $\kappa_{\rm{m}}$ decreases to $1.2\,$MHz at $30\,$mK,
+making this system suitable as a building block for quantum electrodynamics
+experiments. We achieve an electromagnonic cooperativity in excess of $20$ over
+the entire temperature range, with values beyond $100$ in the milliKelvin
+regime as well as at room temperature. With our measurements, spectroscopy on
+strongly coupled magnon-photon systems is demonstrated as versatile tool for
+spin material studies over large temperature ranges. Key parameters are
+provided in a single measurement, thus simplifying investigations
+significantly.",1801.01439v1
+2021-09-09,A low-power integrated magneto-optic modulator on silicon for cryogenic applications,"A fundamental challenge of the quantum revolution is to efficiently interface
+the quantum computing systems operating at cryogenic temperatures with room
+temperature electronics and media for high data-rate communication. Current
+approaches to control and readout of such cryogenic computing systems use
+electrical cables, which prevent scalability due to their large size, heat
+conduction, and limited bandwidth1. A more viable approach is to use optical
+fibers which allow high-capacity transmission and thermal isolation. A key
+component in implementing photonic datalinks is a cryogenic optical modulator
+for converting data from the electrical to the optical domain at high speed and
+with low power consumption, while operating at temperatures of 4 K or lower.
+Cryogenic modulators based on the electro-optic effect have been demonstrated
+in a variety of material platforms, however they are voltage driven components
+while superconducting circuits are current based, resulting in a large
+impedance mismatch. Here, we present the first demonstration of an integrated
+current-driven modulator based on the magneto-optic effect operating over a
+wide temperature range that extends down to less than 4 K. The modulator works
+at data rates up to 2 Gbps with energy consumption below 4 pJ/bit, and we show
+that this figure can be reduced to less than 40 fJ/bit with optimized design
+and fabrication. This modulator is a hybrid device, where a current-driven
+magneto-optically active crystal (cerium substituted yttrium iron garnet, or
+Ce:YIG) is bonded to a high-quality silicon microring resonator. Because of its
+potential for extremely low power consumption under cryogenic conditions, the
+class of magneto-optical modulators demonstrated here has the potential to
+enable efficient data links in large-scale systems for quantum information
+processing.",2109.04538v1
+2021-10-11,Transition of laser-induced terahertz spin currents from torque- to conduction-electron-mediated transport,"Spin transport is crucial for future spintronic devices operating at
+bandwidths up to the terahertz (THz) range. In F|N thin-film stacks made of a
+ferro/ferrimagnetic layer F and a normal-metal layer N, spin transport is
+mediated by (1) spin-polarized conduction electrons and/or (2) torque between
+electron spins. To identify a cross-over from (1) to (2), we study laser-driven
+spin currents in F|Pt stacks where F consists of model materials with different
+degrees of electrical conductivity. For the magnetic insulators YIG, GIG and
+maghemite, identical dynamics is observed. It arises from the THz interfacial
+spin Seebeck effect (SSE), is fully determined by the relaxation of the
+electrons in the metal layer and provides an estimate of the spin-mixing
+conductance of the GIG/Pt interface. Remarkably, in the half-metallic
+ferrimagnet Fe3O4 (magnetite), our measurements reveal two spin-current
+components with opposite direction. The slower, positive component exhibits SSE
+dynamics and is assigned to torque-type magnon excitation of the A- and B-spin
+sublattices of Fe3O4. The faster, negative component arises from the
+pyro-spintronic effect and can consistently be assigned to ultrafast
+demagnetization of e-sublattice minority-spin hopping electrons. This
+observation supports the magneto-electronic model of Fe3O4. In general, our
+results provide a new route to the contact-free separation of torque- and
+conduction-electron-mediated spin currents.",2110.05462v2
+2023-06-28,Degenerate and non-degenerate parametric excitation in YIG nanostructures,"We study experimentally the processes of parametric excitation in microscopic
+magnetically saturated disks of nanometer-thick Yttrium Iron Garnet. We show
+that, depending on the relative orientation between the parametric pumping
+field and the static magnetization, excitation of either degenerate or
+non-degenerate magnon pairs is possible. In the latter case, which is
+particularly important for applications associated with the realization of
+computation in the reciprocal space, a single-frequency pumping can generate
+pairs of magnons whose frequencies correspond to different eigenmodes of the
+disk. We show that, depending on the size of the disk and the modes involved,
+the frequency difference in a pair can vary in the range 0.1-0.8 GHz. We
+demonstrate that in this system, one can easily realize a practically important
+situation where several magnon pairs share the same mode. We also observe the
+simultaneous generation of up to six different modes using a fixed-frequency
+monochromatic pumping. Our experimental findings are supported by numerical
+calculations that allow us to unambiguously identify the excited modes. Our
+results open new possibilities for the implementation of reciprocal-space
+computing making use of low damping magnetic insulators.",2306.16094v1
+2023-08-07,$\textit{In situ}$ electric-field control of ferromagnetic resonance in the low-loss organic-based ferrimagnet V[TCNE]$_{x\sim 2}$,"We demonstrate indirect electric-field control of ferromagnetic resonance
+(FMR) in devices that integrate the low-loss, molecule-based, room-temperature
+ferrimagnet vanadium tetracyanoethylene (V[TCNE]$_{x \sim 2}$) mechanically
+coupled to PMN-PT piezoelectric transducers. Upon straining the V[TCNE]$_x$
+films, the FMR frequency is tuned by more than 6 times the resonant linewidth
+with no change in Gilbert damping for samples with $\alpha = 6.5 \times
+10^{-5}$. We show this tuning effect is due to a strain-dependent magnetic
+anisotropy in the films and find the magnetoelastic coefficient $|\lambda_S|
+\sim (1 - 4.4)$ ppm, backed by theoretical predictions from DFT calculations
+and magnetoelastic theory. Noting the rapidly expanding application space for
+strain-tuned FMR, we define a new metric for magnetostrictive materials,
+$\textit{magnetostrictive agility}$, given by the ratio of the magnetoelastic
+coefficient to the FMR linewidth. This agility allows for a direct comparison
+between magnetostrictive materials in terms of their comparative efficacy for
+magnetoelectric applications requiring ultra-low loss magnetic resonance
+modulated by strain. With this metric, we show V[TCNE]$_x$ is competitive with
+other magnetostrictive materials including YIG and Terfenol-D. This combination
+of ultra-narrow linewidth and magnetostriction in a system that can be directly
+integrated into functional devices without requiring heterogeneous integration
+in a thin-film geometry promises unprecedented functionality for electric-field
+tuned microwave devices ranging from low-power, compact filters and circulators
+to emerging applications in quantum information science and technology.",2308.03353v1