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@ARTICLE{Sandratskii:15214,
author = {Sandratskii, L.M. and Mavropoulos, Ph.},
title = {{M}agnetic excitations and femtomagnetism of {F}e{R}h: {A}
first-principles study},
journal = {Physical review / B},
volume = {83},
number = {17},
issn = {1098-0121},
address = {College Park, Md.},
publisher = {APS},
reportid = {PreJuSER-15214},
pages = {174408},
year = {2011},
note = {Record converted from VDB: 12.11.2012},
abstract = {The paper is partly motivated by recent pump-probe
experiments with ultrashort laser pulses on
antiferromagnetic FeRh that have shown the generation of
magnetization within a subpicosecond time scale. On the
other hand, the physical mechanism of the thermal
antiferromagnetic-ferromagnetic (AFM-FM) phase transition in
FeRh, known for many decades, remains a topic of
controversial discussions. The selection of the magnetic
degrees of freedom as well as the treatment of the magnetic
excited states differ strongly in recent models by different
authors. We report a density functional theory (DFT)
investigation of FeRh. For the study of excited states, DFT
calculations with constraints imposed on the directions and
values of the atomic moments are employed. We show that the
formation of the Rh moment as a consequence of the AFM-FM
phase transition cannot be described within the Stoner
picture. Instead, an implicit spin splitting of the Rh
states takes place in the AFM phase, resulting in the
intra-atomic spin polarization of the Rh atoms. This
property is a consequence of the strong hybridization
between Rh and Fe states. The Fe-Rh hybridization is an
important factor in the physics of FeRh. We demonstrate that
the ferromagnetic Fe-Rh exchange interaction is robust with
respect to the crystal volume variation, whereas the
antiferromagnetic Fe-Fe exchange interaction is strongly
volume dependent. These different volume dependencies of the
competing exchange interactions lead to their strong
compensation at certain crystal volume. We perform Monte
Carlo simulations and show that the calculated
thermodynamics depends on the way the magnetic degrees of
freedom are selected. We argue that the excited states
resulting from the variation of the value of the Rh moment
treated as degree of freedom are important for both the
equilibrium thermodynamics of FeRh and the femtomagnetic
phenomena in this system. We also study the spin mixing
caused by spin-orbit coupling. The obtained value of the
Elliott-Yafet spin-mixing parameter is comparable with
earlier calculations for the ferromagnetic 3d metals. We
draw the conclusion that the Elliott-Yafet mechanism of the
angular-momentum transfer between electrons and lattice
plays an important role in the femtomagnetic properties of
FeRh.},
keywords = {J (WoSType)},
cin = {IAS-1 / PGI-1},
ddc = {530},
cid = {I:(DE-Juel1)IAS-1-20090406 / I:(DE-Juel1)PGI-1-20110106},
pnm = {Grundlagen für zukünftige Informationstechnologien},
pid = {G:(DE-Juel1)FUEK412},
shelfmark = {Physics, Condensed Matter},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000290162000002},
doi = {10.1103/PhysRevB.83.174408},
url = {https://juser.fz-juelich.de/record/15214},
}