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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-di...
1605.08931v1
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 oscillat...
1606.03469v1
2016-07-06
Temperature dependence of the magnon spin diffusion length and magnon spin conductivity in the magnetic insulator yttrium iron garnet
We present a systematic study of the temperature dependence of diffusive magnon spin transport, using a non-local device geometry. In our measurements, we detect spin signals arising from electrical and thermal magnon generation, and we directly extract the magnon spin diffusion length $\lambda_m$ for temperatures from...
1607.01506v1
2016-07-08
Observation of the spin Nernst effect
The observation of the spin Hall effect triggered intense research on pure spin current transport. With the spin Hall effect, the spin Seebeck effect, and the spin Peltier effect already observed, our picture of pure spin current transport is almost complete. The only missing piece is the spin Nernst (-Ettingshausen) e...
1607.02277v2
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 5...
1607.02358v3
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...
1607.03872v1
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 in...
1607.07274v1
2016-08-08
Reconstruction of an effective magnon mean free path distribution from spin Seebeck measurements in thin films
A thorough understanding of the mean-free-path (MFP) distribution of the energy carriers is crucial to engineer and tune the transport properties of materials. In this context, a significant body of work has investigated the phonon and electron MFP distribution, however, similar studies of the magnon MFP distribution h...
1608.02474v3
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 magne...
1609.01613v2
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 s...
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 ...
1609.08147v1
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 eff...
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 b...
1610.08402v2
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 wav...
1610.08756v1
2016-10-27
Observation of Self-Cavitating Envelope Dispersive Shock Waves in Yttrium Iron Garnet Thin Films
The formation and properties of envelope dispersive shock wave (DSW) excitations from repulsive nonlinear waves in a magnetic film are studied. Experiments involve the excitation of a spin-wave step pulse in a low-loss magnetic Y$_3$Fe$_5$O$_{12}$ thin film strip, in which the spin-wave amplitude increases rapidly, rea...
1610.08846v3
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 garne...
1610.09554v1
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 sever...
1610.09963v2
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...
1611.06054v1
2016-12-15
Theory of the Spin Seebeck Effect at a Topological-Insulator/Ferromagnetic-Insulator Interface
The spin-Seebeck effect refers to voltage signals induced in metals by thermally driven spin currents in adjacent magnetic systems. We present a theory of the spin-Seebeck signal in the case where the conductor that supports the voltage signal is the topologically protected two-dimensional surface-state system at the i...
1612.04916v3
2016-12-18
Bottleneck accumulation of hybrid magneto-elastic bosons
It is known that an ensemble of magnons, quanta of spin waves, can be prepared as a Bose gas of weakly interacting quasiparticles with conservation of the particle number. Furthermore, the thermalization of the overpopulated magnon gas can lead to the formation of a Bose-Einstein condensate at the bottom of a spin-wave...
1612.05925v1
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 thicknes...
1612.07239v1
2016-12-15
Experimental prototype of a spin-wave majority gate
Featuring low heat dissipation, devices based on spin-wave logic gates promise to comply with increasing future requirements in information processing. In this work, we present the experimental realization of a majority gate based on the interference of spin waves in an Yttrium-Iron-Garnet-based waveguiding structure. ...
1612.07708v1
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 opposi...
1702.00890v1
2017-02-08
Magnon-polaron transport in magnetic insulators
We theoretically study the effects of strong magnetoelastic coupling on the transport properties of magnetic insulators. We develop a Boltzmann transport theory for the mixed magnon-phonon modes (magnon polarons) and determine transport coefficients and spin diffusion length. Magnon-polaron formation causes anomalous f...
1702.02270v1
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 p...
1702.06038v1
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 energet...
1702.06994v2
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 ...
1705.02267v1
2017-05-09
Low spin wave damping in the insulating chiral magnet Cu$_{2}$OSeO$_{3}$
Chiral magnets with topologically nontrivial spin order such as Skyrmions have generated enormous interest in both fundamental and applied sciences. We report broadband microwave spectroscopy performed on the insulating chiral ferrimagnet Cu$_{2}$OSeO$_{3}$. For the damping of magnetization dynamics we find a remarkabl...
1705.03416v1
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 prec...
1706.01932v2
2017-06-11
Absorbing boundary layers for spin wave micromagnetics
Micromagnetic simulations are used to investigate the effects of different absorbing boundary layers (ABLs) on spin waves (SWs) reflected from the edges of a magnetic nano-structure. We define the conditions that a suitable ABL must fulfill and compare the performance of abrupt, linear, polynomial and tan hyperbolic da...
1706.03325v1
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 rel...
1707.06509v2
2017-09-16
Visualization of Anomalous Ettingshausen Effect in a Ferromagnetic Film: Direct Evidence of Different Symmetry from Spin Peltier Effect
Spatial distribution of temperature modulation due to anomalous Ettingshausen effect (AEE) is visualized in a ferromagnetic FePt thin film with in-plane and out-of-plane magnetizations using the lock-in thermography technique. Comparing the AEE of FePt with the spin Peltier effect (SPE) of a Pt / yttrium iron garnet ju...
1709.05449v1
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...
1710.04179v1
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 wi...
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 ...
1711.00237v2
2017-11-02
Measurement of a Magnonic Crystal at Millikelvin Temperatures
Hybrid systems combining magnons and superconducting quantum circuits have attracted increasing interest in recent years. Magnonic crystals (MCs) are one of the building blocks of room-temperature magnonics and can be used to create devices with an engineered band structure. These devices, exhibiting tunable frequency ...
1711.00958v2
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 PSS...
1712.02561v1
2018-03-30
From Kinetic Instability to Bose-Einstein Condensation and Magnon Supercurrents
Evolution of an overpopulated gas of magnons to a Bose-Einstein condensate and excitation of a magnon supercurrent, propelled by a phase gradient in the condensate wave function, can be observed at room-temperature by means of the Brillouin light scattering spectroscopy in an yttrium iron garnet material. We study thes...
1803.11548v1
2018-04-03
Selection rules for cavity-enhanced Brillouin light scattering from magnetostatic modes
We experimentally identify the magnetostatic modes active for Brillouin light scattering in the optical whispering gallery modes of a yttrium iron garnet sphere. Each mode is identified by magnetic field dispersion of ferromagnetic-resonance spectroscopy and coupling strength to the known field distribution of the micr...
1804.00965v2
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),...
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 ...
1804.03443v1
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{...
1804.04516v1
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-cen...
1804.11231v1
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 (S...
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 s...
1806.04764v1
2018-06-27
Boltzmann approach to the longitudinal spin Seebeck effect
We develop a Boltzmann transport theory of coupled magnon-phonon transport in ferromagnetic insulators. The explicit treatment of the magnon-phonon coupling within the Boltzmann approach allows us to calculate the low-temperature magnetic-field dependence of the spin-Seebeck voltage. Within the Boltzmann theory we find...
1806.10445v1
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 micromagne...
1807.01358v3
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$. Depending on an ...
1807.08481v1
2018-07-24
Enhanced magnon spin transport in NiFe$_2$O$_4$ thin films on a lattice-matched substrate
We investigate magnon spin transport in epitaxial nickel ferrite (NiFe$_2$O$_4$, NFO) films grown on magnesium gallate spinel (MgGa$_2$O$_4$, MGO) substrates, which have a lattice mismatch with NFO as small as 0.78%, resulting in the reduction of antiphase boundary defects and thus in improved magnetic properties in th...
1807.09013v1
2018-10-01
Stabilizing Mechanism for Bose-Einstein Condensation of Interacting Magnons in Ferrimagnets and Ferromagnets
We propose a stabilizing mechanism for the Bose-Einstein condensation (BEC) of interacting magnons in ferrimagnets and ferromagnets. By studying the effects of the magnon-magnon interaction on the stability of the magnon BEC in a ferrimagnet and two ferromagnets, we show that the magnon BEC remains stable even in the p...
1810.00584v2
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 tempe...
1810.08051v2
2018-10-23
Higher-order exceptional point in a cavity magnonics system
We propose to realize the pseudo-Hermiticity in a cavity magnonics system consisting of the Kittel modes in two small yttrium-iron-garnet spheres coupled to a microwave cavity mode. The effective gain of the cavity can be achieved using the coherent perfect absorption of the two input fields fed into the cavity. With c...
1810.09689v3
2018-10-27
Microwave control of thermal magnon spin transport
We observe that an rf microwave field strongly influences the transport of incoherent thermal magnons in yttrium iron garnet. Ferromagnetic resonance in the nonlinear regime suppresses thermal magnon transport by 95%. The transport is also modulated at non-resonant conditions in two cases, both related to the magnon ba...
1810.11667v1
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 frequ...
1811.05801v1
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 ...
1811.05848v1
2018-12-04
Spin transport in a magnetic insulator with zero effective damping
Applications based on spin currents strongly profit from the control and reduction of their effective damping and their transport properties. We here experimentally observe magnon mediated transport of spin (angular) momentum through a 13.4 nm thin yttrium iron garnet film with full control of the magnetic damping via ...
1812.01334v3
2019-01-08
Microscopic theory of spin transport at the interface between the superconductor and a ferromagnetic insulator
We theoretically investigate spin transport at the interface between the ferromagnetic insulator(FI) and a superconductor(SC). Considering a simple FI-SC interface model, we derive formulas for the spin current and spin-current noise induced by microwave irradiation (spin pumping) or the temperature gradient (the spin ...
1901.02440v2
2019-01-26
Chiral excitation of spin waves in ferromagnetic films
We theoretically investigate the interlayer dipolar and exchange couplings for an array of metallic magnetic nanowires grown on top of an extended ultrathin yttrium iron garnet film. The calculated interlayer dipolar coupling agrees with observed anticrossings [Chen \emph{et al.}, Phys. Rev. Lett. \textbf{120}, 217202 ...
1901.09182v1
2019-01-29
Low-impedance superconducting microwave resonators for strong coupling to small magnetic mode volumes
Recent experiments on strongly coupled microwave and ferromagnetic resonance modes have focused on large volume bulk crystals such as yttrium iron garnet, typically of millimeter-scale dimensions. We extend these experiments to lower volumes of magnetic material by exploiting low-impedance lumped-element microwave reso...
1901.10395v1
2019-01-30
Surface dynamics of rough magnetic films
The chirality of Damon-Eshbach (DE) magnons affects the transport of energy and angular momentum at the surface of magnetic films and spheres. We calculate the surface-disorder-limited dephasing and transport lifetimes of surface modes of sufficiently thick high-quality magnetic films such as yttrium iron garnet. In sp...
1901.11046v2
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 spe...
1902.04608v1
2019-03-01
Indirect observation of phase conjugate magnons from non-degenerate four-wave mixing
A phase conjugate mirror utilising four-wave mixing in a magnetic system is experimentally realised for the first time. Indirect evidence of continuous-wave phase conjugation has been observed experimentally and is supported by simulations. The experiment utilizes a pump-probe method to excite a four-wave mixing proces...
1903.00400v1
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 th...
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...
1903.03754v1
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 embedd...
1903.12498v1
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 larg...
1904.04167v1
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 i...
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 d...
1904.10517v1
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 driv...
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 w...
1905.11941v1
2019-05-31
Detecting Light Dark Matter with Magnons
Scattering of light dark matter with sub-eV energy deposition can be detected with collective excitations in condensed matter systems. When dark matter has spin-independent couplings to atoms or ions, it has been shown to efficiently excite phonons. Here we show that, if dark matter couples to the electron spin, magnon...
1905.13744v2
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 S...
1906.01560v3
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 significan...
1906.04469v1
2019-06-24
Macroscopic entanglement of two magnon modes via quantum correlated microwave fields
We present a scheme to entangle two magnon modes in two macroscopic yttrium-iron-garnet spheres. The two spheres are placed inside two microwave cavities, which are driven by a two-mode squeezed microwave field. By using the linear state-swap interaction between the cavity and the magnon mode in each cavity, the quantu...
1906.09921v1
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, exploiti...
1907.00415v4
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 ...
1907.06718v1
2019-07-20
Magnon Bose-Einstein condensate and supercurrents over a wide temperature range
Magnon Bose-Einstein Condensates (BECs) and supercurrents are coherent quantum phenomena, which appear on a macroscopic scale in parametrically populated solid state spinsystems. One of the most fascinating and attractive features of these processes is the possibility of magnon condensation and supercurrent excitation ...
1907.08805v1
2019-08-01
Universal prethermal dynamics in Heisenberg ferromagnets
We study the universal far from equilibrium dynamics of magnons in Heisenberg ferromagnets. We show that such systems exhibit universal scaling in momentum and time of the quasiparticle distribution function, with the universal exponents distinct from those recently observed in Bose-Einstein condensates. This new unive...
1908.00554v2
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 genera...
1909.00085v1
2019-09-27
Thermally driven two-magnet nano-oscillator with large spin-charge conversion
Next-generation spintronic applications require material properties that can be hardly met by one material candidate. Here we demonstrate that by combining insulating and metallic magnets, enhanced spin-charge conversion and energy-efficient thermal spin currents can be realized. We develop a nanowire device consisting...
1909.12445v1
2019-10-16
Spin-Wave frequency division multiplexing in an yttrium iron garnet microstripe magnetized by inhomogeneous field
Spin waves are promising candidates for information processing and transmission in a broad frequency range. In the realization of magnonic devices, the frequency depended division of the spin wave frequencies is a critical function for parallel information processing. In this work, we demonstrate a proof-of-concept spi...
1910.07136v1
2019-10-23
Electrical manipulation of spin pumping signal through nonlocal thermal magnon transport
We study the magnon transport in the nonlocal configuration composed of two Pt strips on top of yttrium iron garnet, with and without the presence of RF microwave generated by an on-chip antenna. We find that the spin-Hall induced thermal magnon heating/cooling, the Oersted field as well as the Joule heating generated ...
1910.10326v2
2019-10-24
Resources of nonlinear cavity magnonics for quantum information
We theoretically explore nonlinearities of ferromagnets in microwave cavities in the classical and quantum regimes, and assess the resources for quantum information, i.e. fluctuation squeezing and bipartite entanglement. The (semi-)classical analysis of the anharmonic oscillator (Duffing) model for the Kittel mode when...
1910.11130v1
2019-10-29
Transient response of spin Peltier effect revealed by lock-in thermoreflectance measurement
Transient response of the spin Peltier effect (SPE) in a Pt/yttrium iron garnet junction system has been investigated by means of a lock-in thermoreflectance method. We applied an alternating charge current to the Pt layer to drive SPE through the spin Hall effect, and measured the AC response of the resultant SPE-indu...
1910.13165v2
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) w...
1910.14117v2
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 couplin...
1910.14470v2
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 ...
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 sys...
1911.11311v1
2019-12-15
Magnon-photon strong coupling for tunable microwave circulators
We present a generic theoretical framework to describe non-reciprocal microwave circulation in a multimode cavity magnonic system and assess the optimal performance of practical circulator devices. We show that high isolation (> 56 dB), extremely low insertion loss (< 0.05 dB), and flexible bandwidth control can be pot...
1912.07128v2
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) an...
2001.05385v1
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 ...
2002.04284v1
2020-02-22
Bose-Einstein Condensation of Nonequilibrium Magnons in Confined Systems
We study the formation of a room temperature magnon Bose-Einstein condensate (BEC) in nanoscopic systems and demonstrate that its lifetime is influenced by the spatial confinement. We predict how dipolar interactions and nonlinear magnon scattering assist in the generation of a metastable magnon BEC in energy-quantized...
2002.09777v2
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...
2003.13760v4
2020-04-11
Brillouin Light Scattering of Spin Waves Inaccessible with Free-Space Light
Micro-focus Brillouin light scattering is a powerful technique for the spectroscopic and spatial characterization of elementary excitations in materials. However, the small momentum of light limits the accessible excitations to the center of the Brillouin zone. Here, we utilize a metallic nanoantenna fabricated on the ...
2004.05314v1
2020-04-25
Pulse-assisted magnetization switching in magnetic nanowires at picosecond and nanosecond timescales with low energy
Detailed understanding of spin dynamics in magnetic nanomaterials is necessary for developing ultrafast, low-energy and high-density spintronic logic and memory. Here, we develop micromagnetic models and analytical solutions to elucidate the effect of increasing damping and uniaxial anisotropy on magnetic field pulse-a...
2004.12243v1
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 in...
2005.04581v3
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 configuratio...
2005.09864v1
2020-06-05
Controlling the nonlinear relaxation of quantized propagating magnons in nanodevices
Relaxation of linear magnetization dynamics is well described by the viscous Gilbert damping processes. However, for strong excitations, nonlinear damping processes such as the decay via magnon-magnon interactions emerge and trigger additional relaxation channels. Here, we use space- and time-resolved microfocused Bril...
2006.03400v2
2020-06-11
Nonlocal magnon entanglement generation in coupled hybrid cavity systems
We investigate dynamical generation of macroscopic nonlocal entanglements between two remote massive magnon-superconducting-circuit hybrid systems. Two fiber-coupled microwave cavities are employed to serve as an interaction channel connecting two sets of macroscopic hybrid units each containing a magnon (hosted by a Y...
2006.06132v3
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...
2006.14257v2