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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...
2402.03734v1
2024-03-04
Double magnetic transition, complex field-induced phases, and large magnetocaloric effect in the frustrated garnet compound Mn$_{3}$Cr$_{2}$Ge$_{3}$O$_{12}$
A detailed study of the magnetic and magnetocaloric properties of a garnet compound Mn$_{3}$Cr$_{2}$Ge$_{3}$O$_{12}$ is carried out using x-ray diffraction, magnetization, heat capacity, and neutron diffraction measurements as well as \textit{ab initio} band-structure calculations. This compound manifests two successiv...
2403.02082v2
2024-03-22
UV- and X-ray-activated broadband NIR garnet-type Ca3Ga2Sn3O12:Fe3+ phosphors with efficient persistent luminescence
Near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) are compact light sources of great interest for NIR spectroscopy applications. Beyond typical Cr3+-activated NIR-emitting phosphors, there exists a strong demand for Cr3+-free alternatives with high efficiency and broadband emission to rich the landsc...
2403.15168v1
2001-04-19
An Empirical Ultraviolet Template for Iron Emission in Quasars as Derived from I Zw 1
We present an empirical template spectrum suitable for fitting/subtracting and studying the FeII and FeIII line emission in the restframe UV spectra of active galatic nuclei (AGNs), the first empirical UV iron template to cover the full 1250 - 3090 A range. Iron emission is often a severe contaminant in optical--UV spe...
0104320v1
2008-10-01
Galactic abundance gradients from Cepheids : On the iron abundance gradient around 10-12 kpc
Context: Classical Cepheids can be adopted to trace the chemical evolution of the Galactic disk since their distances can be estimated with very high accuracy. Aims: Homogeneous iron abundance measurements for 33 Galactic Cepheids located in the outer disk together with accurate distance determinations based on near-in...
0810.0205v1
2011-11-09
Galactic restrictions on iron production by various Types of supernovae
We propose a statistical method for decomposition of contributions to iron production from various sources: supernovae Type II and the subpopulations of supernovae Type Ia -- prompt (their progenitors are short-lived stars of ages less then $\sim$100 Myr) and tardy (whose progenitors are long-lived stars of ages $>$100...
1111.2152v1
2018-08-27
Why Are Some Gamma-Ray Bursts Hosted by Oxygen-rich Galaxies?
Theoretically long gamma-ray bursts (GRBs) are expected to happen in low-metallicity environments, because in a single massive star scenario, low iron abundance prevents loss of angular momentum through stellar wind, resulting in ultra-relativistic jets and the burst. In this sense, not just a simple metallicity measur...
1808.08969v1
2021-03-25
Thermodynamic Analysis of Titanium Removal from Molten iron Smelted with Large Amounts of Sodium Additives
High purity iron is obtained from vanadium-titanium magnetite (VTM) by one-step coal-based direct reduction-smelting process with coal as reductant and sodium carbonate (Na2CO3) as additives. Industrial experiments show that the process of treating molten iron with a large amount of Na2CO3 is effective in removing tita...
2103.13572v1
2021-08-17
Nigral diffusivity, but not free water, correlates with iron content in Parkinson's disease
The loss of melanized neurons in the substantia nigra pars compacta is a primary feature in Parkinson's disease (PD). Iron deposition occurs in conjunction with this loss. Loss of nigral neurons should remove barriers for diffusion and increase diffusivity of water molecules in regions undergoing this loss. In metrics ...
2108.07864v1
2024-01-30
Carrier-phase DNS of ignition and combustion of iron particles in a turbulent mixing layer
Three-dimensional CP-DNS of reacting iron particle dust clouds in a turbulent mixing layer are conducted. The simulation approach considers the Eulerian transport equations for the reacting gas phase and resolves all scales of turbulence, whereas the particle boundary layers are modelled employing the Lagrangian point-...
2401.16944v1
1998-09-10
Abundances of UV bright stars in globular clusters. I. ROA 5701 in omega Centauri and Barnard 29 in M 13
Two UV brights stars in globular clusters, ROA 5701 (omega Cen) and Barnard 29 (M 13) are analysed from high-resolution UV and optical spectra. The main aim is the measurement of iron abundances from UV spectra obtained with the HST-GHRS. In addition atmospheric parameters and abundances for He, C, N, O, and Si are der...
9809128v1
2002-02-05
Iron Features in the XMM-Newton spectrum of NGC 4151
We present a detailed analysis of the hard X-ray (>2.5 keV) EPIC spectra from the first observations of NGC 4151 made by XMM-Newton. We fit the spectra with a model consisting of a power-law continuum modified by line-of-sight absorption (arising in both partially photoionized and neutral gas) plus additional iron-K em...
0202093v1
2004-04-21
Ultra-Low Iron Abundances in Distant Hot Gas in Galaxy Groups
A new XMM observation of the outer regions of the galaxy group NGC 5044 indicates hot gas iron abundances of only ~0.15 solar between r=0.2 - 0.4 r_vir. While the total baryon mass within the virial radius may be close to the cosmic mean value observed in rich clusters, the ratio of total iron mass to optical light in ...
0404430v1
2004-12-28
Model atmospheres and X-ray spectra of iron-rich bursting neutron stars. II. Iron rich Comptonized Spectra
This paper presents the set of plane-parallel model atmosphere equations for a very hot neutron star (X-ray burst source). The model equations assume both hydrostatic and radiative equilibrium, and the equation of state of an ideal gas in local thermodynamic equilibrium (LTE). The equation of radiative transfer include...
0412644v1
2005-08-24
Iron Fluorescent Line Emission from Black Hole Accretion Disks with Magnetic Reconnection-Heated Corona
We investigate the iron K$\alpha$ fluorescent line produced by hard X-ray photons from magnetic reconnection-heated corona. The hot corona with temperature being about $10^9$K can irradiate the underlying disk with a continuum X-ray spectrum produced via thermal Comptonization. Then the iron atoms in the disk photoelec...
0508507v1
2008-04-15
UV and FUV spectroscopy of the hybrid PG 1159-type central star NGC 7094
Previous studies aiming at the iron-abundance determination in three PG 1159 stars (K 1-16, PG 1159-035, NGC 7094) and a [WC]-PG 1159 transition star (Abell 78) have revealed that no object shows any iron line in the UV spectrum. The stars are iron-deficient by at least 1 dex, typically. A possible explanation is that ...
0804.2372v1
2013-06-07
Orbital-dependent effects of electron correlations in microscopic models for iron-based superconductors
The bad metal behavior in the normal state of the iron-based superconductors suggests an intimate connection between the superconductivity and a proximity to a Mott transition. At the same time, there is strong evidence for the multi-orbital nature of the electronic excitations. It is then important to understand the o...
1306.1697v1
2013-06-18
Magnetic anisotropy and lattice dynamics in FeAs studied by Mössbauer spectroscopy
Iron mono-arsenide in the powder form has been investigated by transmission 57Fe Moessbauer spectroscopy in the temperature range 4.2 - 1000 K. Additional spectra have been obtained at 20 K and 100 K applying external magnetic field of 7 T. It was found that the spin spiral propagating along the c-axis leads to the com...
1306.4170v3
2014-06-22
Using iron line reverberation and spectroscopy to distinguish Kerr and non-Kerr black holes
The iron K$\alpha$ line commonly observed in the X-ray spectrum of both stellar-mass and supermassive black hole candidates is produced by the illumination of a cold accretion disk by a hot corona. In this framework, the activation of a new flaring region in the hot corona imprints a time variation on the iron line spe...
1406.5677v3
2014-10-01
Millihertz quasi-periodic oscillations and broad iron line from LMC X-1
We study the temporal and energy spectral characteristics of the persistent black hole X-ray binary LMC X-1 using two XMM-Newton and a Suzaku observation. We report the discovery of low frequency (~ 26-29 mHz) quasi-periodic oscillations (QPOs). We also report the variablity of the broad iron K-alpha line studied earli...
1410.0135v2
2014-11-08
Melting of iron close to Earth's inner core boundary conditions and beyond
Several important geophysical features such as heat flux at the Core-Mantle Boundary or geodynamo production are intimately related with the temperature profile in the Earth's core. However, measuring the melting curve of iron at conditions corresponding to the Earth inner core boundary under pressure of 330 GPa has el...
1411.2074v1
2015-07-06
Unconventional superconductivity in the layered iron germanide YFe$_2$Ge$_2$
Since the discovery of superconductivity in LaFePO in 2006, numerous iron-based superconductors have been identified within diverse structure families, all of which combine iron with a group-V (pnictogen) or group-VI (chalco- gen) element. Unconventional superconductivity is extremely rare among transition metal compou...
1507.01436v2
2015-09-15
Search for New Superconductors: An Electro-Magnetic Phase Transition in an Iron Meteorite Inclusion at 117 K
The discovery of superconductivity in pnictides and iron chalcogenides inspires the search for new iron based superconducting phases. Iron-rich meteorites present a unique opportunity for this search, because they contain a broad range of compounds produced under extreme growth conditions. We investigated a natural iro...
1509.04452v2
2017-04-04
Iron Partitioning between Ferropericlase and Bridgmanite in the Earth's Lower Mantle
Earth's lower mantle is generally believed to be seismically and chemically homogeneous because most of the key seismic parameters can be explained using a simplified mineralogical model at expected press-temperature conditions. However, recent high-resolution tomographic images have revealed seismic and chemical strat...
1704.01140v1
2018-03-05
Iron and silicate dust growth in the Galactic interstellar medium: clues from element depletions
The interstellar abundances of refractory elements indicate a substantial depletion from the gas phase, that increases with gas density. Our recent model of dust evolution, based on hydrodynamic simulations of the lifecycle of giant molecular clouds (GMCs) proves that the observed trend for [Si$_{gas}$/H] is driven by ...
1803.01929v2
2018-08-31
Insight of the thermal conductivity of $ε-$iron at Earth's core conditions from the newly developed direct $ab~initio$ methodology
The electronic thermal conductivity of iron at Earth's core conditions is an extremely important physical property in geophysics field. However, the exact value of electronic thermal conductivity of iron under extreme pressure and temperature still remains poorly known both experimentally and theoretically. A few recen...
1808.10860v1
2019-06-05
Small Planets in the Galactic Context: Host Star Kinematics, Iron, and $α$ Element Enhancement
We explored the occurrence rate of small close-in planets among $\textit{Kepler}$ target stars as a function of the iron abundance and the stellar total velocity $V_\mathrm{tot}$. We estimated the occurrence rate of those planets by combining information from LAMOST and the California-$\textit{Kepler}$ Survey (CKS) and...
1906.01982v2
2020-06-02
Study of iron complexes in visceral organs and brain from a ${}^57$Fe enriched $β$-thalassaemia mouse model via Mössbauer Spectroscopy
The hearts, kidneys, livers, spleens and brains of ${}^57$Fe enriched wild-type and heterozygous $\beta$-thalassaemic mice at 1, 3, 6 and 9 months of age were studied by means of M\"ossbauer Spectroscopy at 80K. Ferritin-like iron depositions in the heart and the brain of the thalassaemic mice were found to be slightly...
2006.01511v1
2021-03-05
Ferromagnetic Composite Self-Arrangement in Iron-Implanted Epitaxial Palladium Thin Films
We report on the formation of the dilute $Pd_{1-x}Fe_x$ compositions with tunable magnetic properties under an ion-beam implantation of epitaxial Pd thin films. Binary $Pd_{1-x}Fe_x$ alloys with a mean iron content $x$ of $0.025$, $0.035$ or $0.075$ were obtained by the implantation of $40 keV$ $Fe^+$ ions into the pal...
2103.03562v1
2021-09-30
Nucleosynthetic Pt isotope anomalies and the Hf-W chronology of core formation in inner and outer solar system planetesimals
The 182Hf-182W chronology of iron meteorites provides crucial information on the timescales of accretion and differentiation of some of the oldest planetesimals of the Solar System. Determining accurate Hf-W model ages of iron meteorites requires correction for cosmic ray expo-sure (CRE) induced modifications of W isot...
2109.15250v1
2021-10-01
Q-Net: A Quantitative Susceptibility Mapping-based Deep Neural Network for Differential Diagnosis of Brain Iron Deposition in Hemochromatosis
Brain iron deposition, in particular deep gray matter nuclei, increases with advancing age. Hereditary Hemochromatosis (HH) is the most common inherited disorder of systemic iron excess in Europeans and recent studies claimed high brain iron accumulation in patient with Hemochromatosis. In this study, we focus on Artif...
2110.00203v1
2021-10-12
Earth's accretion inferred from iron isotopic anomalies of supernova nuclear statistical equilibrium origin
Nucleosynthetic Fe isotopic anomalies in meteorites may be used to reconstruct the early dynamical evolution of the solar system and to identify the origin and nature of the material that built planets. Using high-precision iron isotopic data of 23 iron meteorites from nine major chemical groups we show that all iron m...
2110.06045v1
2022-01-23
Large Impacts onto the Early Earth: Planetary Sterilization and Iron Delivery
Late accretion onto the Hadean Earth included large impacts that could have influenced early habitability, either by sterilizing the planet or alternatively catalyzing the origin of life by delivering iron required to create a reducing environment/atmosphere. We present 3D numerical simulations of 1500-3400 km diameter...
2201.09349v1
2022-04-10
Effect of iron vacancies on the magnetic order and spin dynamics of the spin ladder BaFe$_{2-δ}$S$_{1.5}$Se$_{1.5}$
Quasi-one-dimensional iron chalcogenides possess various magnetic states depending on the lattice distortion, electronic correlations, and presence of defects. We present neutron diffraction and inelastic neutron scattering experiments on the spin ladder compound BaFe$_{2-\delta}$S$_{1.5}$Se$_{1.5}$ with $\sim$6% iron ...
2204.04697v1
2022-04-20
Experimental Simulations of Shock Textures in BCC Iron: Implications for Iron Meteorites
Neumann band in iron meteorites, which is deformation twins in kamacite (Fe-Ni alloy), has been known to be a characteristic texture indicating ancient collisions on parent bodies of meteorites. We conducted a series of shock recovery experiments on bcc iron with the projectile velocity at 1.5 km/sec at various initial...
2204.09195v1
2022-09-11
Correlation-corrected band topology and topological surface states in iron-based superconductors
Iron-based superconductors offer an ideal platform for studying topological superconductivity and Majorana fermions. In this paper, we carry out a comprehensive study of the band topology and topological surface states of a number of iron-based superconductors using a combination of density functional theory (DFT) and ...
2209.04776v1
2023-04-26
Assessment of sol-gel derived iron oxide substituted 45S5 bioglass-ceramics for biomedical applications
Magnetic bioactive glass ceramic (MGC) powders have been synthesized by sol gel route by systematically substituting silicon dioxide with iron oxide in the 45S5 glass composition. Powder x-ray diffraction studies revealed a variation in the percentage of combeite (Ca$_2$Na$_2$Si$_3$O$_9$), magnetite (Fe$_3$O$_4$), and ...
2304.13437v1
2023-11-02
Studying the variability of fluorescence emission and the presence of clumpy wind in HMXB GX 301$-$2 using XMM-Newton
We present the results from an analysis of data from an \textit{XMM-Newton} observation of the accreting high mass X-ray binary pulsar GX 301$-$2. Spectral analysis in the non-flaring segment of the observation revealed that the equivalent width of the iron fluorescence emission is correlated with the observed absorpti...
2311.01176v1
2019-01-15
Dust-depletion sequences in damped Ly-α absorbers II. The composition of cosmic dust, from low-metallicity systems to the Galaxy
We aim at assessing what are the most dominant dust species or types, including silicate and iron oxide grains present in the ISM, by using recent observations of dust depletion of galaxies at various evolutionary stages. We use the observed elemental abundances in dust of several metals (O, S, Si, Mg, and Fe) in diffe...
1901.04710v3
2023-04-28
A comparison of mechanistic models for the combustion of iron microparticles and their application to polydisperse iron-air suspensions
Metals can serve as carbon-free energy carriers, e. g. in innovative metal-metal oxide cycles as proposed by Bergthorson (Prog. Energy Combust. Sci., 2018). Iron powder is a suitable candidate since it can be oxidized with air. Nevertheless, the combustion of iron powder in air is challenging especially with respect to...
2304.14927v2
1994-10-05
Influence of Cooling Flow and Galactic Motion on the Iron Distribution in Clusters of Galaxies
Iron abundance distribution is now known for 12 clusters of galaxies. For some clusters (e.g. Centaurus) the observed abundance increases toward the cluster center, while for the others (e.g. Coma and Hydra-A) no significant inhomogeneity was observed. In order to understand this difference, we investigate the influenc...
9410014v1
1999-11-19
Evolution of iron core white dwarfs
Recent measurements made by Hipparcos (Provencal et al. 1998) present observational evidence supporting the existence of some white dwarf (WD) stars with iron - rich, core composition. In this connection, the present paper is aimed at exploring the structure and evolution of iron - core WDs by means of a detailed and u...
9911371v1
1999-11-19
Gas, Iron and Gravitational Mass in Galaxy Clusters: The General Lack of Cluster Evolution at z < 1.0
We have analyzed the ASCA data of 29 nearby clusters of galaxies systematically, and obtained temperatures, iron abundances, and X-ray luminosities of their intracluster medium (ICM). We also estimate ICM mass using the beta model, and then evaluate iron mass contained in the ICM and derive the total gravitating mass. ...
9911388v1
1999-12-15
On the influence of resonant absorption on the iron emission line profiles from accreting black holes
The fluorescent iron K$\alpha$ emission line profile provides an excellent probe of the innermost regions of active galactic nuclei. Fe XXV and Fe XXVI in diffuse plasma above the accretion disc can affect the X-ray spectrum by iron K$\alpha$ resonant absorption. This in turn can influence the interpretation of the dat...
9912321v1
2000-02-17
The Iron Project
Recent advances in theoretical atomic physics have enabled large-scale calculation of atomic parameters for a variety of atomic processes with high degree of precision. The development and application of these methods is the aim of the Iron Project. At present the primary focus is on collisional processes for all ions ...
0002356v1
2000-09-29
X-ray iron line variability: constraints on the inner accretion disk
After reviewing the basic physics of X-ray reflection in AGN, we present three case studies which illustrate the current state of X-ray reflection studies. For the low-luminosity AGN NGC4258, we find that the iron line is much narrower than is typically found in higher luminosity AGN. We argue that this is evidence for...
0009503v1
2001-06-27
An Empirical Ultraviolet Iron Spectrum Template Applicable to Active Galaxies
Iron emission is often a severe contaminant in optical-ultraviolet spectra of active galaxies. Its presence complicates emission line studies. A viable solution, already successfully applied at optical wavelengths, is to use an empirical iron emission template. We have generated FeII and FeIII templates for ultraviolet...
0106510v1
2002-02-01
Temperature Scale and Iron Abundances of Very Hot Central Stars of Planetary Nebulae
The determination of effective temperatures of very hot central stars (Teff>70000K) by model atmosphere analyses of optical H and He line profiles is afflicted with considerable uncertainty, primarily due to the lack of neutral helium lines. Ionization balances of metals, accessible only with UV lines, allow more preci...
0202012v1
2002-03-14
Cerenkov Line Emission as a Possible Mechanism of X-ray Lines in Gamma-ray Bursts
The recent discoveries of X-ray lines in the afterglows of gamma-ray bursts (GRBs) provide significant clues to the nature of GRB progenitors and central environments. However, the iron line interpretation by fluorescence or recombination mechanism requires a large amount of iron material. We argue that the very strong...
0203222v2
2003-05-13
Iron and Nickel properties in the X-ray reflecting region of the Circinus Galaxy
We discuss the iron and nickel properties in the nuclear X-ray reflecting region of the Circinus Galaxy, studied with XMM-Newton. The main results are: a) from the depth of the Fe Kalpha edge, a value of A_Fe=1.7 in number with respect to the cosmic value (as for Anders & Grevesse 1989) is measured, if the (not directl...
0305217v1
2003-06-25
Iron K features in the hard X-ray XMM-Newton spectrum of NGC 4151
Recent XMM-Newton observations have measured the hard (2.5-12 keV) X-ray spectrum of the well-known Seyfert galaxy NGC 4151 with a signal-to-noise unprecedented for this source. We find that a spectral model, developed to fit previous Beppo-SAX and ASCA observations of NGC 4151, provides an excellent description of the...
0306540v1
2003-08-11
Theoretical UBVRI colors of iron core white dwarfs
We explore photometric properties of hypothetical iron core white dwarfs and compute their expected colors in UBVRI Johnson broadband system. Atmospheres of iron core WDs in this paper consist of pure iron covered by a pure hydrogen layer of an arbitrary column mass. LTE model atmospheres and theoretical spectra are ca...
0308184v2
2006-09-12
Discoveries of Diffuse Iron Line Sources from the Sgr B Region
The radio complex Sgr B region is observed with the X-Ray Imaging Spectrometers (XIS) on board Suzaku. This region exhibits diffuse iron lines at 6.4, 6.7 and 6.9 keV, which are K$\alpha$ lines of Fe \emissiontype{I} (neutral iron), Fe\emissiontype{XXV} (He-like iron) and Fe\emissiontype{XXVI} (H-like iron), respective...
0609310v1
2006-07-08
Magnetic Magnetoelectric and Magnetoelastic Properties of new multiferroic material NdFe3(BO3)4
Complex experimental and theoretical study of the magnetic, magnetoelectric, and magnetoelastic properties of neodymium iron borate NdFe3(BO3)4 along various crystallographic directions have been carried out in strong pulsed magnetic fields up to 230 kOe in a temperature range of 4.2-50 K. It has been found that neodym...
0607217v1
2005-09-14
Role of proton irradiation and relative air humidity on iron corrosion
This paper presents a study of the effects of proton irradiation on iron corrosion. Since it is known that in humid atmospheres, iron corrosion is enhanced by the double influence of air and humidity, we studied the iron corrosion under irradiation with a 45% relative humidity. Three proton beam intensities (5, 10 and ...
0509116v1
2005-09-14
Origin of the hydrogen involved in iron corrosion under irradiation
In the perspective of long term geological storage, high level nuclear wastes will be overpacked in low carbon steel containers. In that context, we have studied the influence of oxygen dissolved in water on iron corrosion. Therefore, leaching experiments were performed in desaerated D$\_2$O and in aerated H$\_2$O and ...
0509117v1
2005-09-14
Use ion beam techniques to study the coupling between air and its relative humidity on iron corrosion under irradiation
In this paper, the role of air humidity on the iron corrosion under irradiation is studied in the context of geological disposal of nuclear wastes. The irradiation experiments are performed at room temperature using a 3 MeV extracted proton beam with a 10 nA intensity. Different atmospheres are studied: Humid air with ...
0509120v1
2007-10-25
Nuclear PDFs from neutrino deep inelastic scattering
We study nuclear effects in charged current deep inelastic neutrino-iron scattering in the frame-work of a chi^2 analysis of parton distribution functions. We extract a set of iron PDFs and show that under reasonable assumptions it is possible to constrain the valence, light sea and strange quark distributions. Our iro...
0710.4897v2
2007-10-25
Topology of the Spin-polarized Charge Density in bcc and fcc Iron
We investigate the topology of the spin-polarized charge density in bcc and fcc iron. While the total spin-density is found to possess the topology of the non-magnetic prototypical structures, in some cases the spin-polarized densities are characterized by unique topologies; for example, the spin-polarized charge densi...
0710.4942v2
2007-11-19
XMM-Newton and Broad Iron Lines
Iron line emission is common in the X-ray spectra of accreting black holes. When the line emission is broad or variable then it is likely to originate from close to the black hole. X-ray irradiation of the accretion flow by the power-law X-ray continuum produces the X-ray 'reflection' spectrum which includes the iron l...
0711.2976v1
2008-03-26
Supernova progenitors and iron density evolution from SN rate evolution measurements
Using an extensive compilation of literature supernova rate data we study to which extent its evolution constrains the star formation history, the distribution of the type Ia supernova (SNIa) progenitor's lifetime, the mass range of core-collapse supernova (CCSN) progenitors, and the evolution of the iron density in th...
0803.3793v2
2008-07-01
Light matter in the core of the Earth: its identity, quantity and temperature using tricritical phenomena
Light elements in the iron-rich core of the Earth are important indicators for the evolution of our planet. Their amount and distribution, and the temperature in the core, are essential for understanding how the core and the mantle interact and for modelling the geodynamo which generates the planetary magnetic field. H...
0807.0187v1
2008-08-15
Relativistic Iron Line Emission from the Neutron Star Low-mass X-ray Binary 4U 1636-536
We present an analysis of XMM-Newton and RXTE data from three observations of the neutron star LMXB 4U 1636-536. The X-ray spectra show clear evidence of a broad, asymmetric iron emission line extending over the energy range 4-9 keV. The line profile is consistent with relativistically broadened Fe K-alpha emission fro...
0808.2214v2
2009-02-11
Temperature of the inner-core boundary of the Earth: Melting of iron at high pressure from first-principles coexistence simulations
The Earth's core consists of a solid ball with a radius of 1221 Km, surrounded by a liquid shell which extends up to 3480 Km from the centre of the planet, roughly half way towards the surface (the mean radius of the Earth is 6373 km). The main constituent of the core is iron, and therefore the melting temperature of i...
0902.1831v1
2009-05-23
Kinetic Magnetism and Orbital Order in Iron Telluride
Iron telluride (FeTe), a relative of the iron based high temperature superconductors, displays unusual magnetic order and structural transitions. Here we explore the idea that strong correlations may play an important role in these materials. We argue that the unusual orders observed in FeTe can be understood from a pi...
0905.3782v1
2009-07-02
Moessbauer spectroscopy evidence for the lack of iron magnetic moment in superconducting FeSe
Superconducting FeSe has been investigated by measurements of the magnetic susceptibility versus temperature and Moessbauer spectroscopy at various temperatures including strong external magnetic fields applied to the absorber. It was found that isomer shift exhibits sharply defined increase at about 105 K leading to t...
0907.0383v2
2010-06-19
High resolution spectroscopic study of red clump stars in the Galaxy: iron group elements
The main atmospheric parameters and abundances of the iron group elements (vanadium, chromium, iron, cobalt and nickel) are determined for 62 red giant "clump" stars revealed in the Galactic field by the Hipparcos orbiting observatory. The stars form a homogeneous sample with the mean value of temperature T=4750 +- 160...
1006.3857v1
2010-07-19
Can an underestimation of opacity explain B-type pulsators in the SMC?
Slowly Pulsating B and $\beta$ Cephei are $\kappa$ mechanism driven pulsating B stars. That $\kappa$ mechanism works since a peak in the opacity due to a high number of atomic transitions from iron-group elements occurs in the area of $\log T \approx 5.3$. Theoretical results predict very few SPBs and no $\beta$ Cep to...
1007.3088v1
2010-11-12
Spin waves in the $(π,0)$ magnetically ordered iron chalcogenide Fe$_{1.05}$Te
We use inelastic neutron scattering to show that the spin waves in the iron chalcogenide Fe$_{1.05}$Te display novel dispersion clearly different from those in the related iron pnictide systems. By fitting the spin waves to a Heisenberg Hamiltonian, we extract magnetic exchange couplings that are dramatically different...
1011.2930v2
2010-12-02
Interstitial Iron Controlled Superconductivity in Fe1+xTe0.7Se0.3
The superconducting series, Fe(Te,Se), has a complex structural and magnetic phase diagram that is dependent on composition and occupancy of a secondary interstitial Fe site. In this letter, we show that superconductivity in Fe1+xTe0.7Se0.3 can be enhanced by topotactic deintercalation of the interstitial iron, demonst...
1012.0590v1
2010-12-31
Binary and nonbinary description of hypointensity in human brain MR images
Accumulating evidence has shown that iron is involved in the mechanism underlying many neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease and Huntington's disease. Abnormal (higher) iron accumulation has been detected in the brains of most neurodegenerative patients, especially in the basal ga...
1101.0242v1
2011-01-25
Quantum criticality in the iron pnictides and chalcogenides
Superconductivity in the iron pnictides and chalcogenides arises at the border of antiferromagnetism, which raises the question of the role of quantum criticality. In this topical review, we describe the theoretical work that led to the prediction for a magnetic quantum critical point arising out of a competition betwe...
1101.4701v1
2011-02-22
Magneto-elastic quantum fluctuations and phase transitions in the iron superconductors
We examine the relevance of magneto-elastic coupling to describe the complex magnetic and structural behaviour of the different classes of the iron superconductors. We model the system as a two-dimensional metal whose magnetic excitations interact with the distortions of the underlying square lattice. Going beyond mean...
1102.4622v2
2012-12-05
Progress in wire fabrication of iron-based superconductors
Iron-based superconductors, with Tc values up to 55 K, are of great interest for applications, due to their lower anisotropies and ultrahigh upper critical fields. In the past 4 years, great progress has been made in the fabrication of iron-based superconducting wires and tapes using the powder-in-tube (PIT) processing...
1212.1207v1
2013-05-30
Searching for the missing iron in the core of the Centaurus cluster
We re-analyse a combined 198 ks Chandra observation of NGC4696, the brightest galaxy of the Centaurus cluster. We extract temperature and metallicity profiles from the data, and we confirm the presence of a sharp drop in iron abundance, from ~1.8 Zsolar to ~0.4 Zsolar, within the central 5 kpc of the cluster. We estima...
1305.7046v3
2013-08-13
The unique electronic structure of Ca10(Pt4As8)(Fe2-xPtxAs2)5 with metallic Pt4As8 layers
We studied the low-lying electronic structure of the newly discovered iron-platinum-arsenide superconductor, Ca10(Pt4As8)(Fe2-xPtxAs2)5 (Tc=22 K) with angle-resolved photoemission spectroscopy. We found that the Pt4As8 layer contributes to a small electron-like Fermi surface, indicative of metallic charge reservoir lay...
1308.3105v1
2013-12-03
Disk emission and atmospheric absorption lines in black hole candidate 4U 1630-472
We re-analyzed SUZAKU data of the black hole candidate 4U 1630-472 being in the high/soft state. We show that the continuum X-ray spectrum of 4U 1630-472 with iron absorption lines can be satisfactorily modeled by the spectrum from an accretion disk atmosphere. Absorption lines of highly ionized iron originating in hot...
1312.0922v1
2014-05-22
Electronic structure of iron-based superconductors: from pnictides to chalcogenides and other similar systems
This review discusses and compares electronic spectra of new iron-based high-temperature superconductors (HTSC), as well as a number of chemically similar compounds. Particular attention is payed to iron chalcogenide K_{1-x}Fe_{2-y}Se_2, which is isostructural to BaFe_2As_2 (122) pnictide. It is shown, that Fermi surfa...
1405.5677v1
2014-05-26
Dynamic transition in supercritical iron
Recent advance in understanding the supercritical state posits the existence of a new line above the critical point separating two physically distinct states of matter: rigid liquid and non-rigid gas-like fluid. The location of this line, the Frenkel line, remains unknown for important real systems. Here, we map the Fr...
1405.6491v1
2014-06-13
Effect of dopants on thermal stability and self-diffusion in iron nitride thin films
We studied the effect of dopants (Al, Ti, Zr) on the thermal stability of iron nitride thin films prepared using a dc magnetron sputtering technique. Structure and magnetic characterization of deposited samples reveal that the thermal stability together with soft magnetic properties of iron nitride thin films get signi...
1406.3446v1
2014-06-14
Emergence of magnetism and controlling factors of superconductivity in Li/Na-ammonia co-intercalated FeSe1-zTez
The discovery of superconductivity in alkali-ammonia co-intercalated FeSe has generated intensive interest because of their highest Tc (~ 45 K) among iron-chalcogenide superconductors with bulk form. Here, we report the phase diagrams of two series of Li/Na-ammonia co-intercalated FeSe1-zTez. When superconductivity is ...
1406.3733v2
2014-07-18
Magnetism and Superconductivity in Iron-based Superconductors Decided by Condensed Particle-hole Excitations away from the Fermi Level
The origin of magnetism and superconductivity in iron-based superconductors is still unclear. Here, by investigating the momentum-dependent particle-hole excitations which quantify the tendency of itinerant electrons towards various magnetic states or superconducting phases, we unravel a novel origin to account for the...
1407.4888v1
2015-01-08
The origin of the spurious iron spread in the globular cluster NGC 3201
NGC 3201 is a globular cluster suspected to have an intrinsic spread in the iron content. We re-analysed a sample of 21 cluster stars observed with UVES-FLAMES at the Very Large Telescope and for which Simmerer et al. found a 0.4 dex wide [Fe/H] distribution with a metal-poor tail. We confirmed that when spectroscopic ...
1501.01968v1
2015-03-08
Antiferromagnetic order and spin dynamics in iron-based superconductors
High-transition temperature (high-$T_c$) superconductivity in the iron pnictides/chalcogenides emerges from the suppression of the static antiferromagnetic order in their parent compounds, similar to copper oxides superconductors. This raises a fundamental question concerning the role of magnetism in the superconductiv...
1503.02340v2
2015-09-05
Iron abundance in the atmosphere of Arcturus
Abundance of iron in the atmosphere of Arcturus has been determined from the profiles or regions of the profiles of the weak lines sensitive to iron abundance. The selected lines of Fe I and Fe II were synthesized with the MARCS theoretical models of the atmosphere. From the observed profiles of lines available with a ...
1509.01700v1
2015-10-22
Internal structure of Pluto and Charon with an iron core
Pluto has been observed by the New Horizons space probe to have some relatively fresh ice on the old ices covering most of the surface. Pluto was thought to consist of only a rocky core below the ice. Here I show that Pluto can have an iron core, as can also its companion Charon, which has recently been modelled to hav...
1510.06604v1
2016-01-05
Testing the Kerr nature of black hole candidates using iron line reverberation mapping in the CPR framework
The iron K$\alpha$ line commonly observed in the X-ray spectrum of black hole candidates is produced by X-ray fluorescence of the inner accretion disk. This line can potentially be quite a powerful tool to probe the spacetime geometry around these objects and test the Kerr black hole hypothesis. In a previous paper, we...
1601.00838v2
2016-01-27
Particle-Hole Transformation in Strongly-Doped Iron-Based Superconductors
An exact particle-hole transformation is discovered in a local-moment model for a single layer of heavily electron-doped FeSe. The model harbors hidden magnetic order between the iron d_xz and d_yz orbitals at the wavenumber (pi,pi). It potentially is tied to the magnetic resonances about the very same Neel ordering ve...
1601.07479v3
2016-02-13
Origin of the Broad Iron Line Feature and the Soft X-ray Variation in Seyfert Galaxies
Many Seyfert galaxies are known to exhibit significant X-ray spectral variations and seemingly broad iron K-emission line features. In this paper, we show that the "variable partial covering model", which has been successfully proposed for MCG-6.30-15 (Miyakawa, Ebisawa & Inoue 2012) and 1H0707.495 (Mizumoto, Ebisawa &...
1602.04284v1
2016-03-10
Ferromagnetism and particle collisions: applications to protoplanetary disks and the meteoritical record
The meteoritical record shows both iron partitioning and tungsten isotopic partitioning between matrix and chondrules. Tungsten is not abundant enough to have driven its own isotopic partitioning, but if tungsten were correlated with iron, then ferromagnetic interactions grains could help explain both observations. We ...
1603.03326v1
2016-04-28
Mössbauer parameters of Fe-related defects in group-IV semiconductors: first principles calculations
We employ a combination of pseudopotential and all-electron density functional calculations, to relate the structure of defects in supercells to the isomer shifts and quadrupole splittings observed in M\"ossbauer spectroscopy experiments. The methodology is comprehensively reviewed and applied to the technologically re...
1604.08425v2
2016-05-13
Crystal Chemistry and Structural Design of Iron-Based Superconductors
The second class of high-temperature superconductors (HTSCs), iron-based pnictides and chalcogenides, necessarily contain Fe$_2$$X_2$ ("$X$" refers to a pnictogen or a chalcogen element) layers, just like the first class of HTSCs which possess the essential CuO$_2$ sheets. So far, dozens of iron-based HTSCs, classified...
1605.04179v1
2016-06-14
Ab-initio perspective on structural and electronic properties of iron-based superconductors
The discovery of iron pnictides and iron chalcogenides as a new class of unconventional superconductors in 2008 has generated an enourmous amount of experimental and theoretical work that identifies these materials as correlated metals with multiorbital physics, where magnetism, nematicity and superconductivity are com...
1606.04411v1
2016-12-07
Direct observation of dispersive lower Hubbard band in iron-based superconductor FeSe
Electronic correlations were long suggested not only to be responsible for the complexity of many novel materials, but also to form essential prerequisites for their intriguing properties. Electronic behavior of iron-based superconductors is far from conventional, while the reason for that is not yet understood. Here w...
1612.02313v1
2017-01-10
Orbital-driven two-dome superconducting phases in iron-based superconductors
Recent several experiments revealed that novel bipartite magnetic/superconducting phases widely exist in iron pnictides and chalcogenides. Nevertheless, the origin of the two-dome superconducting phases in iron-based compounds still remains unclear. Here we theoretically investigated the electronic structures, magnetic...
1701.02500v1
2017-01-31
SANS contrast variation study of magnetoferritin structure at various iron loading
Magnetoferritin, a synthetic derivate of iron storage protein - ferritin, has been synthesized with different iron oxide loading values. Small-angle neutron scattering experiments were applied to study the structure of magnetoferritin solutions using contrast variation method by varying the light to heavy water ratio o...
1701.09174v1
2017-01-30
Effect of iron oxide loading on magnetoferritin structure in solution as revealed by SAXS and SANS
Synthetic biological macromolecule of magnetoferritin containing an iron oxide core inside a protein shell (apoferritin) is prepared with different content of iron. Its structure in aqueous solution is analyzed by small-angle synchrotron X-ray (SAXS) and neutron (SANS) scattering. The loading factor (LF) defined as the...
1702.00350v1
2017-03-09
Transport properties of iron at the Earth's core conditions: the effect of spin disorder
The electronic and thermal transport properties of the Earth's core are crucial for many geophysical models such as the geodynamo model of the Earth's magnetic field and of its reversals. Here we show, by considering bcc-iron and iron-rich iron-silicon alloy as a representative of the Earth's core composition and apply...
1703.03205v3
2017-03-19
Surface anisotropy of iron oxide nanoparticles and slabs from first principles : influence of coatings and ligands as a test of the Heisenberg model
We performed ab initio computations of the magnetic properties of simple iron oxide clusters and slabs. We considered an iron oxide cluster functionalized by a molecule or glued to a gold cluster of the same size. We also considered a magnetite slab coated by cobalt oxide or a mixture of iron oxide and cobalt oxide. Th...
1703.06414v1
2017-06-16
Robotic Ironing with 3D Perception and Force/Torque Feedback in Household Environments
As robotic systems become more popular in household environments, the complexity of required tasks also increases. In this work we focus on a domestic chore deemed dull by a majority of the population, the task of ironing. The presented algorithm improves on the limited number of previous works by joining 3D perception...
1706.05340v1