publicationDate stringlengths 1 2.79k | title stringlengths 1 36.5k ⌀ | abstract stringlengths 1 37.3k ⌀ | id stringlengths 9 47 |
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2019-11-20 | Suppression of superconductivity by spin fluctuations in iron-based superconductors | We study the superconducting instability mediated by spin fluctuations in the
Eliashberg theory for a minimal two-band model of iron-based superconductors.
While antiferromagnetic spin fluctuations can drive superconductivity (SC) as
is well established, we find that spin fluctuations necessarily contain a
contribution... | 1911.09009v3 |
2020-02-08 | Atomic diffusion in alpha-iron across the Curie point: an effcient and transferable ab-initio-based modelling approach | An accurate prediction of atomic diffusion in Fe alloys is challenging due to
thermal magnetic excitations and magnetic transitions. We propose an effcient
approach to address these properties via Monte Carlo simulation, using
ab-initio based effective interaction models. The temperature evolution of
self- and Cu diffu... | 2002.03126v2 |
2020-03-23 | Inverse heat source problem and experimental design for determining iron loss distribution | Iron loss determination in the magnetic core of an electrical machine, such
as a motor or a transformer, is formulated as an inverse heat source problem.
The sensor positions inside the object are optimized in order to minimize the
uncertainty in the reconstruction in the sense of the A-optimality of Bayesian
experimen... | 2003.10395v2 |
2020-04-10 | Baby MIND detector first physics run | Baby MIND is a Magnetized Iron Neutrino Detector, serving as a downstream
magnetized muon range detector for WAGASCI on the T2K beam line in Japan. The
first physics run of Baby MIND together with other WAGASCI sub-detectors took
place in the period from November 2019 to February 2020 (T2K run10), where a
total of $4.8... | 2004.05245v1 |
2020-09-03 | Measurements of sub-nT dynamic magnetic field shielding with soft iron and mu-metal for use in linear colliders | There is an increasing need to shield beams and accelerator elements from
stray magnetic fields. The application of magnetic shielding in linear
colliders is discussed. The shielding performance of soft iron and mu-metal is
measured for magnetic fields of varying amplitude and frequency. Special
attention is given to c... | 2009.01519v2 |
2020-10-18 | Some comments on events associated with falling terrestrial rocks and iron from the sky | Some examples of the events associated with falls of rocks and iron
terrestrial origin from the sky are considered (in scientific publications they
are often called as meteor-wrongs or pseudo-meteorites). Their possible
connections with other natural phenomena (like a whirlwind and a
ball-lightning) are considered. Som... | 2012.00686v1 |
2021-04-15 | Surface orbital order and chemical potential inhomogeneity of the iron-based superconductor FeTe0.55Se0.45 investigated with special STM tips | The atomically clean surface of the iron-based superconductor FeTe0.55Se0.45
is investigated by low-temperature STM with different tip apex states. By
manipulating a single Fe atom onto the tip apex, signatures of the orbital
nature of the subsurface Fe layer of FeTe0.55Se0.45 can be identified. By
preparing a charged ... | 2104.07418v1 |
2021-05-23 | Ab initio investigation of impurity ferromagnetism in the Pd1-xFex alloys: concentration and position dependence | We present the ab initio results of the structural and magnetic properties of
the Pd host matrix implanted with Fe solute atoms at various concentrations. By
means of density functional theory we confirm that iron impurities are able to
initialize significant magnetization of the Pd atoms, when the impurity
consentatio... | 2105.10918v1 |
2021-09-20 | Quantile Regression for positive data using a general class of distributions | This paper presents a general class of quantile regression models for
positive continuous data. In this class of models we consider that the response
variable has a IRON distribution. We provide inference and diagnostic tools for
this class of models. An R package, called IRON, was implemented. This package
provides es... | 2109.09281v1 |
2021-09-26 | Monte Carlo simulation of ultrafast nonequilibrium spin and charge transport in iron | Spin transport and spin dynamics after femtosecond laser pulse irradiation of
iron (Fe) are studied using a kinetic Monte Carlo model. This model simulates
spin dependent dynamics by taking into account two interaction processes during
nonequilibrium: Elastic electron - lattice scattering, where only the direction
of t... | 2109.12578v1 |
2021-11-22 | Electron and Superconducting Properties of the AFeAs (A= Li, Na) Family Alkali-Metal Pnictides: Current Stage of the Research (mini-review) | The review is focused on one of the most exotic families of iron-based
superconductors belonging to the AFeAs structural type, where A is alkali
metal. We briefly concern physical and electron properties of the typical
members of this family, LiFeAs and NaFeAs, discuss the theoretical models
describing the multiple-gap... | 2111.11122v1 |
2022-03-11 | Electrical Conductivity of Iron in Earth's Core from Microscopic Ohm's Law | Understanding the electronic transport properties of iron under high
temperatures and pressures is essential for constraining geophysical processes.
The difficulty of reliably measuring these properties under Earth-core
conditions calls for sophisticated theoretical methods that can support
diagnostics. We present resu... | 2203.06025v1 |
2022-07-18 | Direct observation of the spin exciton in Andreev spectroscopy of iron-based superconductors | Quasiparticle excitations provide viable information on the physics of
unconventional superconductors. Higgs and Leggett modes are some of the classic
examples. Another important bosonic excitation is the spin exciton originating
from the sign-changing superconducting gap structure. Here we report a direct
observation ... | 2207.08493v2 |
2023-01-11 | Mathematical and Physical Properties of Three-Band s+- Eliashberg Theory for Iron Pnictides | The phenomenology of the iron pnictide superconductor can be described by the
threeband s+- Eliashberg theory in which the mechanism of superconducting
coupling is mediated by antiferromagnetic spin fluctuations and whose
characteristic energy W0 scales with Tc according to the empirical law W0 =
4.65kBTc. This model p... | 2301.04557v1 |
2023-05-04 | Iron-based superconductors: teenage, complex, challenging | The advent of iron-based superconductors in 2008 came as a complete surprise
to the condensed matter community. Now 15 years later, they are beginning to
impart some of their new-found wisdom on a slew of emerging superconductors
that boast similar traits. | 2305.03035v1 |
2023-08-26 | Multivariate Majorization in Principal-Agents Models | We introduce a definition of multivariate majorization that is new to the
economics literature. Our majorization technique allows us to generalize Mussa
and Rosen's (1978) "ironing" to a broad class of multivariate principal-agents
problems. Specifically, we consider adverse selection problems in which agents'
types ar... | 2308.13804v1 |
2023-10-10 | Ab initio description of bcc iron with correlation matrix renormalization theory | We applied the ab initio spin-polarized Correlation Matrix Renormalization
Theory (CMRT) to the ferromagnetic state of the bulk BCC iron. We showed that
it was capable of reproducing the equilibrium physical properties and the
pressure-volume curve in good comparison with experiments. We then focused on
the analysis of... | 2310.06942v1 |
1994-06-07 | Abundances of four very metal-poor stars of the BPS survey | High resolution CASPEC and EMMI spectra (R$\approx$10$^4$) of the faint
metal- deficient candidates CS 22891--209, CS 22897--8, CS 22948--66 and CS
22968--14 taken from the survey of Beers, Preston and Shectman (1985, BPS) are
analyzed for abundances. The fine analysis with LTE model atmospheres gives an
iron metallici... | 9406018v1 |
1995-03-14 | CHEMICAL ABUNDANCES IN CLUSTERS OF GALAXIES | We study the origin of iron and alpha-elements (O, Mg, Si) in clusters of
galaxies. In particular, we discuss the [O/Fe] ratio and the iron
mass-to-luminosity ratio in the intracluster medium (ICM) and their link to the
chemical and dynamical evolution of elliptical and lenticular galaxies. We
adopt a detailed model of... | 9503057v1 |
1995-07-24 | Good Abundances from Bad Spectra: I. Techniques | We have developed techniques to extract true iron abundances and surface
gravities from spectra of the type provided by the multiple-object fibre-fed
spectroscopic radial-velocity surveys underway with 2dF, HYDRA, NESSIE, and the
forthcoming Sloan survey. Our method is optimised for low S/N, intermediate
resolution blu... | 9507091v1 |
1997-06-09 | Iron as a tracer in galaxy clusters and groups | Available X-ray data are collected and organized concerning the iron and gas
content of galaxy clusters and groups, together with the optical luminosity,
mass and iron abundance of cluster galaxies. Several astrophysical inferences
are then drawn, including the evidence for rich clusters having evolved without
much bar... | 9706083v1 |
1997-10-07 | Ionization Structure and Spectra of Iron in Gaseous Nebulae} | The emission spectra and the ionization structure of the low ionization
stages of iron, Fe I--IV, in gaseous nebulae are studied. This work includes:
(i) new atomic data: photoionization cross sections, total e-ion recombination
rates, excitation collision strengths, and transition probabilities; (ii)
detailed study of... | 9710073v1 |
1999-06-24 | X-ray iron line variability for the model of an orbiting flare above a black hole accretion disc | The broad X-ray iron line, detected in many active galactic nuclei, is likely
to be produced by fluorescence from the X-ray illuminated central parts of an
accretion disc close to a supermassive black hole. The time-averaged shape of
the line can be explained most naturally by a combination of special and
general relat... | 9906397v1 |
1999-07-26 | Model Photospheres for Late-Type Stars from the Inversion of High-Resolution Spectroscopic Observations. Groombridge 1830 and Epsilon Eridani | An inversion technique to recover LTE one-dimensional model photospheres for
late-type stars, which was previously applied to the Sun (Allende Prieto et al.
1998), is now employed to reconstruct, semi-empirically, the photospheres of
cooler dwarfs: the metal-poor Gmb1830 and the active star of solar-metallicity
Eps Eri... | 9907368v1 |
1999-12-17 | Discovery of a red and blue shifted iron disk line in the galactic jet source GRO J1655-40 | We report the discovery of emission features in the X-ray spectrum of GRO
J1655-40 obtained with RXTE during the observation of 1997, Feb 26. We have
fitted the features firstly by two Gaussian lines which in four spectra
analysed have average energies of 5.85 +/- 0.08 keV and 7.32 +/- 0.13 keV,
strongly suggestive tha... | 9912389v2 |
2000-03-07 | The Chandra Iron-L X-Ray Line Spectrum of Capella | An analysis of the iron L-shell emission in the publicly available spectrum
of the Capella binary system, as obtained by the High Energy Transmission
Grating Spectrometer on board the Chandra X-ray Observatory, is presented. The
atomic-state model, based on the HULLAC code, is shown to be especially
adequate for analyz... | 0003099v3 |
2000-03-27 | Atomic data from the Iron Project.XLIV. Transition probabilities and line ratios for Fe VI with fluorescent excitation in planetary nebulae | Relativistic atomic structure calculations for electric dipole E1, electric
quadrupole E2 and magnetic dipole M1 transition probabilities among the first
80 fine-structure levels of Fe VI, dominated by configurations 3d^3, 3d^24s,
and 3d^24p, are carried out using the Breit-Pauli version of the code
Superstructure. Exp... | 0003410v1 |
2000-06-13 | Hot HB stars in globular clusters - Physical parameters and consequences for theory. V. Radiative levitation versus helium mixing | Atmospheric parameters (effective temperature Teff, surface gravity log g),
masses and helium abundances are derived for 42 hot horizontal branch (HB)
stars in the globular cluster NGC 6752. For 19 stars we derive magnesium and
iron abundances as well and find that iron is enriched by a factor of 50 on
average with res... | 0006182v2 |
2000-12-13 | XMM-Newton observation of the Tycho Supernova Remnant | We present the observation of the Tycho supernova remnant obtained with the
EPIC and RGS instruments onboard the XMM-Newton satellite. We compare images
and azimuthally averaged radial profiles in emission lines from different
elements (silicon and iron) and different transition lines of iron (Fe L and Fe
K). While the... | 0012288v1 |
2001-01-25 | Evolution of Iron K$_α$ Line Emission in the Black Hole Candidate GX 339-4 | GX 339-4 was regularly monitored with RXTE during a period (in 1999) when its
X-ray flux decreased significantly (from 4.2$\times 10^{-10}$ erg cm$^{-2}
s^{-1}$ to 7.6$\times 10^{-12}$ erg cm$^{-2}$s$^{-1}$ in the 3--20 keV band),
as the source settled into the ``off state''. Our spectral analysis revealed
the presence... | 0101459v1 |
2001-04-03 | On the absorption feature in the prompt X-ray spectrum of GRB 990705 | The absorption feature detected in the prompt X-ray emission of GRB 990705
bears important consequences. We investigate different production mechanisms
and we conclude that the absorbing material cannot be very close to the burster
and is likely to be moderately clumped. These properties challenge any model in
which th... | 0104062v1 |
2001-06-17 | Are Stars with Planets Polluted? | We compare the metallicities of stars with radial velocity planets to the
metallicity of a sample of field dwarfs. We confirm recent work indicating that
the stars-with-planet sample as a whole is iron rich. However, the lowest mass
stars tend to be iron poor, with several having [Fe/H]<-0.2, demonstrating that
high me... | 0106294v1 |
2002-01-16 | An X-ray view of the active nucleus in NGC 4258 | XMM-Newton observed the Seyfert 1.9 galaxy NGC 4258 in December 2000. At
energies above 2 keV a hard nuclear point source is resolved that can be fitted
by a highly absorbed power-law spectrum (NH = (8.0+-0.4)x10^22 cm^-2, photon
index 1.64+-0.08) with an unabsorbed luminosity of 7.5x10^40erg/s in the 2-10
keV band. No... | 0201267v1 |
2003-01-13 | Spectral variations of the X-ray binary pulsar LMC X-4 during its long period intensity variation and a comparison with Her X-1 | We present spectral variations of the binary X-ray pulsar LMC X-4 using the
RXTE/PCA observations at different phases of its 30.5 day long super-orbital
period. Only out of eclipse data were used for this study. During the high
state of the super-orbital period of LMC X-4, the spectrum is well described by
a high energ... | 0301208v1 |
2003-02-13 | The variability of accretion onto Schwarzschild black holes from turbulent magnetized discs | We use global magnetohydrodynamic simulations, in a pseudo-Newtonian
potential, to investigate the temporal variability of accretion discs around
Schwarzschild black holes. We use the vertically-averaged magnetic stress in
the simulated disc as a proxy for the rest-frame dissipation, and compute the
observed emission b... | 0302271v1 |
2003-03-06 | Iron K alpha line profiles and the inner boundary condition of accretion flows | Recent X-ray observations have shown evidence for exceptionally broad and
skewed iron K alpha emission lines from several accreting black hole systems.
The lines are assumed to be due to fluorescence of the accretion disk
illuminated by a surrounding corona and require a steep emissivity profile
increasing in to the in... | 0303143v1 |
2003-05-13 | Iron abundance in the ICM at high redshift | We present the analysis of the X-ray spectra of 18 distant clusters of
galaxies with redshift 0.3 < z < 1.3. Most of them were observed with the
Chandra satellite in long exposures ranging from 36 ks to 180 ks. For two of
the z>1 clusters we also use deep XMM-Newton observations. Overall, these
clusters probe the tempe... | 0305223v1 |
2003-08-15 | The impact of pollution on stellar evolution models | An approach is introduced for incorporating the concept of stellar pollution
into stellar evolution models. The approach involves enhancing the metal
content of the surface layers of stellar models. In addition, the surface
layers of stars in the mass range of 0.5-2.0 Solar masses are mixed to an
artificial depth motiv... | 0308267v1 |
2003-09-23 | Does the Iron K$_α$ Line of Active Galactic Nuclei Arise from the Cerenkov Line-like Radiation? | When thermal relativistic electrons with isotropic distribution of velocities
move in a gas region, or impinge upon the surface of a cloud that consists of a
dense gas or doped dusts, the Cerenkov effect produces peculiar atomic or ionic
emission lines -- the Cerenkov line-like radiation. This newly recognized
emission... | 0309604v1 |
2003-09-29 | The Type-Ia Supernova Rate in z < 1 Galaxy Clusters: Implications for Progenitors and the Source of Cluster Iron | The iron mass in galaxy clusters is about 6 times larger than could have been
produced by core-collapse supernovae (SNe), assuming the stars in the cluster
formed with a standard initial mass function (IMF). SNe Ia have been proposed
as the alternative dominant iron source. Different SN Ia progenitor models
predict dif... | 0309797v1 |
2004-02-25 | Oxygen Overabundance in the Extremely Iron-Poor Star CS29498-043 | An abundance analysis for the carbon-enhanced, extremely iron-poor ([Fe/H]
-3.5) star CS29498-043 has been obtained using new high-resolution, high
signal-to-noise spectra from the Subaru Telescope. The [O I] forbidden line at
6300A and the O I triplet feature at 7771-7776A are both clearly detected. The
overabundance ... | 0402585v1 |
2004-05-11 | Photoionization Modeling and the K Lines of Iron | We calculate the efficiency of iron K line emission and iron K absorption in
photoionized models using a new set of atomic data. These data are more
comprehensive than those previously applied to the modeling of iron K lines
from photoionized gases, and allow us to systematically examine the behavior of
the properties ... | 0405210v1 |
2004-07-17 | Time-dependent Circulation Flows: Iron Enrichment in Cooling Flows with Heated Return Flows | We describe a new type of dynamical model for hot gas in galaxy groups and
clusters in which gas moves simultaneously in both radial directions.
Circulation flows are consistent with (1) the failure to observe cooling gas in
X-ray spectra, (2) multiphase gas observed near the centers of these flows and
(3) the accumula... | 0407367v1 |
2004-10-28 | Hydrodynamic model atmospheres for WR stars: Self-consistent modeling of a WC star wind | We present the first non-LTE atmosphere models for WR stars that incorporate
a self-consistent solution of the hydrodynamic equations. The models account
for iron-group line-blanketing and clumping, and compute the hydrodynamic
structure of a radiatively driven wind consistently with the non-LTE radiation
transport in ... | 0410697v1 |
2005-06-13 | Brief history of the metal accumulation in the intracluster medium | We use models of the rates of Type Ia supernovae (SNe Ia) and core-collapse
supernovae, built in such a way that both are consistent with recent
observational constraints at z<1.6 and can reproduce the measured cosmic star
formation rate, to recover the history of the metals accumulation in the
intra-cluster medium. We... | 0506272v2 |
2006-10-03 | The iron K feature in Narrow Line Seyfert 1's: evidence for a P Cygni profile? | Narrow Line Seyfert 1 galaxies are generally accreting at high fractions of
the Eddington limit. They can show complex X-ray spectra, with a strong `soft
excess' below 2 keV and a sharp drop at ~7 keV. There is strong evidence
linking the soft excess to either reflection or absorption from relativistic,
partially ioniz... | 0610078v1 |
2006-11-21 | The origin of the strong soft excess and puzzling iron line complex in Mkn 841 | Mkn 841 has been observed during 3 different periods (January 2001, January
2005 and July 2005) by XMM-Newton for a total cumulated exposure time of ~108
ks. We present in this paper a broad band spectral analysis of the complete
EPIC-pn data sets. These observations confirm the presence of the strong soft
excess and c... | 0611665v1 |
2007-03-16 | On the Iwasawa-Taniguchi effect of radio-quiet AGN | The existence of an anti-correlation between the Equivalent Width (EW) of the
neutral narrow core of the iron Kalpha emission line and the 2-10 keV
luminosity (the so-called `X-ray Baldwin' or `Iwasawa-Taniguchi' effect) has
been debated in the last years. We aim at testing this claim on the largest
catalogue of radio ... | 0703433v1 |
2005-12-26 | Anisotropic Correlations in Epitaxial Iron Silicide: Contribution of Surface and Bulk States | Scanning tunneling microscopy | 0512643v2 |
1999-03-22 | Effect on a Hadron Shower Leakage on the Energy Response and Resolution of Hadron TILE Calorimeter | The hadronic shower longitudinal and lateral leakages and its effect on the
pion response and energy resolution of iron-scintillator barrel hadron
prototype calorimeter with longitudinal tile configuration with a thickness of
9.4 nuclear interaction lengths have been investigated. The results are based
on 100 GeV pion ... | 9903051v1 |
2007-10-15 | Transition from galactic to extragalactic cosmic rays | The transition from galactic to extragalactic cosmic rays is discussed. One
of critical indications for transition is given by the Standard Model of
Galactic cosmic rays, according to which the maximum energy of acceleration for
iron nuclei is of order of $E_{\rm Fe}^{\rm max} \approx 1\times 10^{17}$ eV.
At $E > E_{\r... | 0710.2750v2 |
2008-01-10 | On why the Iron K-shell absorption in AGN is not a signature of the local Warm/Hot Intergalactic Medium | We present a comparison between the 2001 XMM-Newton and 2005 Suzaku
observations of the quasar, PG1211+143 at z=0.0809. Variability is observed in
the 7 keV iron K-shell absorption line (at 7.6 keV in the quasar frame), which
is significantly weaker in 2005 than during the 2001 XMM-Newton observation.
From a recombinat... | 0801.1587v1 |
2008-02-01 | The iron abundance of the Magellanic Bridge | High-resolution HST ultra-violet spectra for five B-type stars in the
Magellanic Bridge and in the Large and Small Magellanic Clouds have been
analysed to estimate their iron abundances. Those for the Clouds are lower than
estimates obtained from late-type stars or the optical lines in B-type stars by
approximately 0.5... | 0802.0132v1 |
2008-07-28 | Nature of Magnetic Interactions and Inelastic Neutron Scattering as a Probe of Magnetic Excitations in Iron-Pnictide Superconductors | This submission has been withdrawn by the arXiv admins because it is an
abstract only, which is against arXiv policy. | 0807.4351v2 |
2008-08-29 | What will be the maximum Tc in the iron-based superconductors? | Using the newly developed real space vortex-lattice based theory of
superconductivity, we study the maximum superconducting transition temperature
(T_{c}^{\max}) in the iron-based superconductors. We find that all the reported
FeAs superconductors can be divided into two basic classes (c/a=3 and c/a=5/2)
depending on t... | 0808.4093v3 |
2008-09-01 | Spin Fluctuation Dynamics and Multiband Superconductivity in Iron Pnictides | Multiband superconductivity, involving resonant pair scattering between
different bands, has emerged as a possible explanation of some of the main
characteristics of the recently discovered iron pnictides. A key feature of
such interband pairing mechanism is that it can generate or enhance
superconducting pairing irres... | 0809.0014v1 |
2008-10-15 | A Large Iron Isotope Effect in SmFeAsO1-xFx and Ba1-xKxFe2As2 | The recent discovery of superconductivity in oxypnictides with the critical
temperature (TC) higher than McMillan limit of 39 K (the theoretical maximum
predicted by Bardeen-Cooper-Schrieffer (BCS) theory) has generated great
excitement. Theoretical calculations indicate that the electron-phonon
interaction is not stro... | 0810.2694v2 |
2009-01-12 | Electrodynamics in Iron and Steel | In order to calculate the reflected EM fields at low amplitudes in iron and
steel, more must be understood about the nature of long wavelength excitations
in these metals. A bulk piece of iron is a very complex material with
microstructure, a split band structure, magnetic domains and crystallographic
textures that aff... | 0901.1631v2 |
2009-03-16 | Spin Waves and Magnetic Exchange Interactions in CaFe2As2 | Antiferromagnetism is relevant to high temperature (high-Tc)
superconductivity because copper oxide and iron arsenide high-Tc
superconductors arise from electron- or hole-doping of their antiferromagnetic
(AF) ordered parent compounds. There are two broad classes of explanation for
the phenomenon of antiferromagnetism:... | 0903.2686v1 |
2009-04-02 | The layered iron arsenides Sr2CrO3FeAs and Ba2ScO3FeAs | Polycrystalline samples of the layered iron arsenides Sr2CrO3FeAs and
Ba2ScO3FeAs were synthesized by high temperature solid state reactions and
their crystal structures determined by the X-ray powder diffraction. Their
structures are tetragonal (P4/nmm; Sr2CrO3FeAs: a = 391.12(1) pm, c =
1579.05(3) pm; Ba2ScO3FeAs: a ... | 0904.0479v2 |
2009-05-21 | Integer and half-integer flux-quantum transitions in a niobium/iron-pnictide loop | The recent discovery of iron-based superconductors challenges the existing
paradigm of high-temperature superconductivity. Owing to their unusual
multi-orbital band structure, magnetism, and electron correlation, theories
propose a unique sign reversed s-wave pairing state, with the order parameter
changing sign betwee... | 0905.3571v2 |
2009-05-25 | A double stellar generation in the Globular Cluster NGC6656 (M 22). Two stellar groups with different iron and s-process element abundance | AIMS. In this paper we present the chemical abundance analysis from high
resolution UVES spectra of seventeen bright giant stars of the Globular Cluster
M~22. RESULTS. We obtained an average iron abundance of [Fe/H]=-1.76\pm0.02
(internal errors only) and an \alpha enhancement of 0.36\pm0.04 (internal
errors only). Na ... | 0905.4058v1 |
2009-06-29 | A novel wear-resistant magnetic thin film material based on a $Ti_{1-x}Fe_xC_{1-y}$ nanocomposite alloy | In this study we report on the film growth and characterization of thin
(approximately 50 nm thick) Ti-Fe-C films deposited on amorphous quartz. The
experimental studies have been complemented by first principles density
functional theory (DFT) calculations. Upon annealing of as-prepared films, the
composition of the m... | 0906.5386v1 |
2009-09-02 | A homogeneous spectroscopic analysis of host stars of transiting planets | The analysis of transiting extra-solar planets provides an enormous amount of
information about the formation and evolution of planetary systems. A precise
knowledge of the host stars is necessary to derive the planetary properties
accurately. The properties of the host stars, especially their chemical
composition, are... | 0909.0285v1 |
2009-10-20 | The Distribution and Cosmic Density of Relativistic Iron Lines in Active Galactic Nuclei | X-ray observations of several active galactic nuclei show prominent iron
K-shell fluorescence lines that are sculpted due to special and general
relativistic effects. These observations are important because they probe the
space-time geometry close to distant black holes. However, the intrinsic
distribution of Fe line ... | 0910.3947v1 |
2010-03-09 | A comparison of hard X-ray photon indices and iron \ka emission lines in X-ray luminous narrow- and broad-line Seyfert 1 galaxies | We use publicly available XMM-Newton data to systematically compare the hard
X-ray photon indices, $\Gamma_{\rm 2-10\ keV}$ and the iron K$\alpha$ emission
lines of narrow-line (NL) and broad-line Seyfert 1 (BLS1) galaxies. We compile
a flux-limited ($f_{\rm 2-10\ keV} \geq 1 \times 10^{-12}$ erg s$^{-1}$
cm$^{-2}$) sa... | 1003.1772v2 |
2010-04-08 | The final verdict by XMM-Newton: the X-ray obscured Seyfert galaxy NGC5506 has a broad Fe K-alpha line | We present the first unambiguous evidence of a broad (Gaussian width ~330 eV)
component of the iron K-alpha fluorescent emission line in the X-ray obscured
Narrow Line Seyfert 1 Galaxy NGC5506. This is the main results of a
spectroscopic monitoring campaign on this source performed with the XMM-Newton
observatory betwe... | 1004.1442v1 |
2010-06-11 | Mott Transition in Multi-Orbital Models for Iron Pnictides | The bad-metal behavior of the iron pnictides has motivated a theoretical
description in terms of a proximity to Mott localization. Since the parent
compounds of the iron pnictides contain an even number of 3d-electrons per Fe,
it is important to determine whether a Mott transition robustly exists and the
nature of the ... | 1006.2337v3 |
2010-07-29 | Looking into the inner black hole accretion disc with relativistic models of iron line | We discuss black hole spin measurements employing the relativistic iron line
profiles in the X-ray domain. We investigate the iron line band for two
representative sources -- MCG -6-30-15 (active galaxy) and GX 339-4 (X-ray
binary). We compare two models of the broad iron line, LAOR and KYRLINE. We
realise that the spi... | 1007.5196v2 |
2010-08-16 | Pulse-phase resolved spectroscopy of continuum and reflection in SAX J1808.4-3658 | We perform phase-resolved spectroscopy of the accreting millisecond pulsar,
SAX J1808.4-3658, during the slow-decay phase of the 2002 outburst. Simple
phenomenological fits to RXTE PCA data reveal a pulsation in the iron line at
the spin frequency of the neutron star. However, fitting more complex spectral
models revea... | 1008.2708v2 |
2011-04-04 | Interplay between magnetism and superconductivity in iron-chalcogenide superconductors: crystal growth and characterizations | In this review, we present a summary of the results on single crystal growth
of two types of iron-chalcogenide superconductors, Fe(1+y)Te(1-x)Se(x) (11),
and A(x)Fe(2-y)Se(2) (A= K, Rb, Cs, Tl, Tl/K, Tl/Rb), using Bridgman,
zone-melting, vapor self-transport, and flux techniques. The superconducting
and magnetic proper... | 1104.0695v2 |
2011-04-18 | Kinetic frustration and the nature of the magnetic and paramagnetic states in iron pnictides and iron chalcogenides | The iron pnictide and chalcogenide compounds are a subject of intensive
investigations due to their high temperature superconductivity.\cite{a-LaFeAsO}
They all share the same structure, but there is significant variation in their
physical properties, such as magnetic ordered moments, effective masses,
superconducting ... | 1104.3454v1 |
2011-04-26 | Electronic and magnetic phase diagram in K$_x$Fe$_{2-y}$Se$_2$ superconductors | The correlation and competition between antiferromagnetism and
superconductivity are one of the most fundamental issues in all of high
temperature superconductors. The superconductivity in high temperature cuprate
superconductors arises from suppressing an antiferromagnetic (AFM) Mott
insulator phase by doping1 while t... | 1104.4941v1 |
2011-05-13 | First Principles Calculations of Defects in Unstable Crystals: Austenitic Iron | First principles calculations have given a new insight into the energies of
point defects in many different materials, information which cannot be readily
obtained from experiment. Most such calculation are done at zero Kelvin, with
the assumption that finite temperature effects on defect energies and barriers
are smal... | 1105.2663v1 |
2011-05-16 | On the apparent absence of broad iron lines in Seyfert galaxies | We present an analysis of XMM-Newton observations of eleven Seyfert galaxies
that appear to be missing a broad iron K alpha line. These objects represent a
challenge to the established paradigm for active galactic nuclei, where a
relatively cold accretion disc feeds the central black hole. In that paradigm,
X-ray illum... | 1105.3065v1 |
2011-07-26 | Interplay between magnetism and superconductivity in EuFe(2-x)Co(x)As2 studied by 57Fe and 151Eu Mössbauer spectroscopy | The compound EuFe(2-x)Co(x)As2 was investigated by means of the 57Fe and
151Eu Moessbauer spectroscopy versus temperature (4.2 - 300 K) for x=0
(parent), x=0.34 - 0.39 (superconductor) and x=0.58 (overdoped). It was found
that spin density wave (SDW) is suppressed by Co-substitution, however it
survives in the region o... | 1107.5271v2 |
2011-07-26 | Superconductivity up to 35 K in the iron-platinum arsenides (CaFe1-xPtxAs)10Pt4-yAs8 with layered structures | We report the synthesis and crystal structures of three new superconducting
iron-platinum arsenides (CaFe1-xPtxAs)10Pt4-yAs8 (x = 0-0.15, y = 0-0.4). The
structures are stacking variants of FeAs- and slightly puckered Pt4-yAs8-layers
with square coordinated platinum separated by calcium-layers, respectively.
Arsenic at... | 1107.5320v1 |
2011-08-02 | Weak-interaction mediated rates on iron isotopes for presupernova evolution of massive stars | During the presupernova evolution of massive stars, the isotopes of iron,
$^{54,55,56}$Fe, are advocated to play a key role inside the cores primarily
decreasing the electron-to-baryon ratio ($Y_{e}$) mainly via electron capture
processes thereby reducing the pressure support. Electron decay and positron
capture on $^{... | 1108.0507v1 |
2011-08-24 | Energy spectra of primary and secondary cosmic-ray nuclei measured with TRACER | The TRACER cosmic-ray detector, first flown on long-duration balloon (LDB) in
2003 for observations of the major primary cosmic-ray nuclei from oxygen (Z=8)
to iron (Z=26), has been upgraded to also measure the energies of the lighter
nuclei, including the secondary species boron (Z=5). The instrument was used in
anoth... | 1108.4838v1 |
2011-10-10 | X-ray Diagnostics of Giant Molecular Clouds in the Galactic Center Region and Past Activity of Sgr A* | Strong iron fluorescence at 6.4 keV and hard-X-ray emissions from giant
molecular clouds in the Galactic center region have been interpreted as
reflections of a past outburst of the Sgr A* supermassive black hole. Careful
treatment of multiple interactions of photons in a complicated geometry is
essential to modeling t... | 1110.1936v1 |
2011-10-12 | Reemerging superconductivity at 48 K across quantum criticality in iron chalcogenides | Pressure plays an essential role in the induction1 and control2,3 of
superconductivity in iron-based superconductors. Substitution of a smaller
rare-earth ion for the bigger one to simulate the pressure effects has
surprisingly raised the superconducting transition temperature Tc to the record
high 55 K in these materi... | 1110.2600v3 |
2011-11-02 | Structural quantum criticality and superconductivity in iron-based superconductor Ba(Fe1-xCox)2As2 | We investigated the elastic properties of the iron-based superconductor
Ba(Fe1-xCox)2As2 with eight Co concentrations. The elastic constant C66 shows
large elastic softening associated with the structural phase transition. The
C66 was analyzed base on localized and itinerant pictures of Fe-3d electrons,
which shows the... | 1111.0366v1 |
2011-12-05 | Pairing symmetries of several families of iron-based superconductors and some similarities with cuprates and heavy-fermions | We show that, by using unit-cell transformation between 1 Fe per unit cell to
2 Fe per unit cell, one can qualitatively understand the pairing symmetry of
several families of iron-based superconductors. In iron-pnictides and
iron-chalcogenides, the nodeless s+- pairing and the resulting magnetic
resonance mode transfor... | 1112.1004v1 |
2012-02-29 | Muon Background Reduction in CLIC | We report on a study concerning the reduction of muon backgrounds in CLIC
using magnetised iron. | 1202.6628v1 |
2012-03-30 | The role of different negatively charged layers in Ca10(Fe1-xPtxAs)10(Pt3+yAs8) and superconductivity at 30 K in electron-doped (Ca0.8La0.2)10(FeAs)10(Pt3As8) | The recently discovered compounds Ca10(Fe1-xPtxAs)10(Pt3+yAs8) exhibit
superconductivity up to 38 K, and contain iron arsenide (FeAs) and platinum
arsenide (Pt3+yAs8) layers separated by layers of Ca atoms. We show that high
Tc's above 15 K only emerge if the iron-arsenide layers are at most free of
platinum-substituti... | 1203.6767v1 |
2012-04-11 | Strong pairing at iron $3d_{xz,yz}$ orbitals in hole-doped BaFe$_2$As$_2$ | Among numerous hypotheses, recently proposed to explain superconductivity in
iron-based superconductors [1-9], many consider Fermi surface (FS) nesting [2,
4, 8, 10] and dimensionality [4, 9] as important contributors. Precise
determination of the electronic spectrum and its modification by
superconductivity, crucial f... | 1204.2432v1 |
2012-06-01 | Error estimates for binomial approximations of game put options | We construct algorithms via binomial approximations for computation of prices
of game put options and obtain estimates of approximation errors. | 1206.0153v2 |
2012-07-03 | Suzaku Observation of Strong Fluorescent Iron Line Emission from the Young Stellar Object V1647 Ori during Its New X-ray Outburst | The Suzaku X-ray satellite observed the young stellar object V1647 Ori on
2008 October 8 during the new mass accretion outburst reported in August 2008.
During the 87 ksec observation with a net exposure of 40 ks, V1647 Ori showed a
high level of X-ray emission with a gradual decrease in flux by a factor of 5
and then ... | 1207.0774v1 |
2012-07-18 | MARS Star Density Results for Shielding Applications | Comparison of MARS 15.09 star density results in thick shielding to the star
density distribution in iron and concrete rule-of-thumb expectations. | 1207.4457v1 |
2012-07-24 | From d-wave to s-wave pairing in the iron-pnictide superconductor (Ba,K)Fe2As2 | The nature of the pairing state in iron-based superconductors is the subject
of much debate. Here we argue that in one material, the stoichiometric iron
pnictide KFe2As2, there is overwhelming evidence for a d-wave pairing state,
characterized by symmetry-imposed vertical line nodes in the superconducting
gap. This evi... | 1207.5719v1 |
2012-07-27 | The Gutzwiller Density Functional Theory | In this tutorial presentation, we give a comprehensive introduction into the
Gutzwiller variational approach and its merger with the density functional
theory. The merits of this method are illustrated by a discussion of results
for two-band Hubbard models and realistic multi-band Hamiltonians for
iron-pnictide systems... | 1207.6456v1 |
2012-08-24 | Conformity of spin fluctuations in alkali-metal iron selenide superconductors inferred from the observation of a magnetic resonant mode in K(x)Fe(2-y)Se(2) | Spin excitations stemming from the metallic phase of the ferrochalcogenide
superconductor K(0.77)Fe(1.85)Se(2) (T_c=32 K) were mapped out in the ab plane
by means of the time-of-flight neutron spectroscopy. We observed a magnetic
resonant mode at Q_res=(1/2 1/4), whose energy and in-plane shape are almost
identical to ... | 1208.5033v1 |
2012-09-26 | Overview on the physics and materials of the new superconductor KxFe2-ySe2 | Since the discovery of high temperature superconductivity in iron pnictides
in early 2008, many iron-based superconductors with different structures have
been discovered, with the highest transition temperature to date being 57 K. By
the end of 2010, another kind of new superconductor, the Fe-based chalcogenide
K1-xFe2... | 1209.5945v1 |
2012-10-05 | Rapid Microwave-Assisted Synthesis of Dextran-Coated Iron Oxide Nanoparticles for Magnetic Resonance Imaging | Currently, magnetic iron oxide nanoparticles are the only nano-sized magnetic
resonance imaging (MRI) contrast agents approved for clinical use, yet
commercial manufacturing of these agents has been limited or discontinued.
Though there is still widespread demand for these particles both for clinical
use and research, ... | 1210.1827v1 |
2013-02-19 | Improper s-wave symmetry for the electronic pairing in iron-based superconductors by first-principles calculation | By means of space-group symmetry arguments, we argue that the electronic
pairing in iron-based high temperature superconductors shows a structure which
is a linear combination of planar s-wave and d-wave symmetry channels, both
preserving the 3-dimensional A_1g irreducible representation of the
corresponding crystal po... | 1302.4748v2 |
2013-02-25 | Highly Correlated Electron State and High-Temperature Superconductivity in Iron Pnictides | It is shown that the qualitative model of the high-temperature
superconductivity suggested earlier for cuprates and doped picene and based on
the idea that the valence electron state depends on the character of the
chemical bonds they form and on the Coulomb interaction between the electrons
is not only confirmed by th... | 1302.6002v4 |
2013-03-27 | Solubility of Iron in Metallic Hydrogen and Stability of Dense Cores in Giant Planets | The formation of the giant planets in our solar system, and likely a majority
of giant exoplanets, is commonly explained by the accretion of nebular hydrogen
and helium onto a large core of terrestrial-like composition. The fate of this
core has important consequences for the evolution of the interior structure of
the ... | 1303.6743v1 |
2013-05-16 | Pseudogap formation above the superconducting dome in iron-pnictides | The nature of the pseudogap in high transition temperature (high-Tc)
superconducting cuprates has been a major issue in condensed matter physics. It
is still unclear whether the high-Tc superconductivity can be universally
associated with the pseudogap formation. Here we provide direct evidence of the
existence of the ... | 1305.3875v2 |
2013-09-13 | Separation of antiferromagnetism and high-temperature superconductivity in Ca$_{1-x}$La$_x$Fe$_2$As$_2$ under pressure | We report the effect of applied pressures on magnetic and superconducting
order in single crystals of the aliovalent La-doped iron pnictide material
Ca$_{1-x}$La$_{x}$Fe$_{2}$As$_{2}$. Using electrical transport, elastic neutron
scattering and resonant tunnel diode oscillator measurements on samples under
both quasi-hy... | 1309.3576v1 |
2013-12-27 | Fe-vacancy order and superconductivity in PbO-type tetragonal β-Fe1-xSe | Several superconducting transition temperatures in the range of 30-40 K were
reported in the recently discovered intercalated FeSe sytem (A1-xFe2-ySe2, A =
K, Rb, Cs, Tl). Although the superconducting phases were not yet conclusively
decided, more than one magnetic phase with particular orders of iron vacancy
and/or po... | 1312.7255v1 |
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