Atomic long-range order effects on Curie temperature and adiabatic spin-wave dynamics in strained Fe-Co alloy films

Schönecker, Stephan; Li, Xiaoqing; Johansson, Börje; Vitos, Levente

doi:10.1103/physrevb.94.064410

Cited by 2 publications

(1 citation statement)

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“…These studies addressed the origin of large MAE in thin films [22], superlattices [13,23] and bulk samples [4,[24][25][26][27], as well as its dependence on chemical composition [4, 13, 17-20, 22, 28] and chemical order [22,26,29]. A mechanism of large MAE was proposed by Burkert et al, who showed that it can be caused by peculiarities of electronic states near the Fermi level [4].…”

Section: Introductionmentioning

confidence: 99%

Coulomb correlations and magnetic properties of L10 FeCo: A DFT+DMFT study

Белозеров

Катанин

Анисимов

2022

Phys. Rev. Materials

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We consider electronic correlation effects and their impact on magnetic properties of tetragonally distorted chemically ordered FeCo alloys (L1 0 structure) being a promising candidate for rare-earthfree permanent magnets. We employ a state-of-the-art method combining density functional and dynamical mean-field theory. According to our results, the predicted Curie temperature reduces with increase of lattice parameters ratio c/a and reaches nearly 850 K at c/a = 1.22. For all considered c/a from 1 to √ 2, we find well-localized magnetic moments on Fe sites, which are formed due to strong correlations originating from Hund's coupling. At the same time, magnetism of Co sites is more itinerant with a much less lifetime of local magnetic moments. However, these short-lived local moments are also formed due to Hund's exchange. Electronic states at Fe sites are characterized by a non-quasiparticle form of self-energies, while the ones for Co sites are found to have a Fermi-liquid-like shape with quasiparticle mass enhancement factor m * /m ∼ 1.4, corresponding to moderately correlated metal. The strong electron correlations on Fe sites leading to Hund's metal behaviour can be explained by peculiarities of the density of states, which has pronounced peaks near the Fermi level, while weaker many-body effects on Co sites can be caused by stronger deviation from half-filling of their 3d states. The obtained momentum dependence of magnetic susceptibility suggests that the ferromagnetic ordering is the most favourable one except for the near vicinity of the fcc structure and the magnetic exchange is expected to be of RKKY type.

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Section: Introductionmentioning

confidence: 99%

Coulomb correlations and magnetic properties of L10 FeCo: A DFT+DMFT study

Белозеров

Катанин

Анисимов

2022

Phys. Rev. Materials

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show abstract

Coulomb correlations and magnetic properties of L1$_0$ FeCo: a DFT+DMFT study

Belozerov,

Katanin,

Anisimov

2022

Preprint

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We consider electronic correlation effects and their impact on magnetic properties of tetragonally distorted chemically ordered FeCo alloy (L1 0 structure) being a promising candidate to rare-earthfree permanent magnets. We employ a state-of-the-art method combining the density functional (DFT) and dynamical mean-field theory (DMFT). According to our results, the predicted Curie temperature reduces with increase of lattice parameters ratio c/a and reaches nearly 850 K at c/a = 1.22. For all considered c/a from 1 to √ 2 we find well-localized magnetic moments on Fe sites, which are formed due to strong correlations originating from Hund's coupling. At the same time, magnetism of Co sites is more itinerant with a much less lifetime of local magnetic moments. However, these short-lived local moments are also formed due to Hund's exchange.Electronic states at Fe sites are characterized by non-quasiparticle form of self-energies, while the ones for Co sites are found to have a Fermi-liquid-like shape with quasiparticle mass enhancement factor m * /m ∼ 1.4, corresponding to moderately correlated metal. The strong electron correlations on Fe sites leading to Hund's metal behaviour can be explained by peculiarities of density of states, which has pronounced peaks near the Fermi level, while weaker many-body effects on Co sites can be caused by stronger deviation from half-filling of their 3d states. The obtained momentum dependence of magnetic susceptibility suggests that the ferromagnetic ordering is the most favourable one except for the near vicinity of the fcc structure and the magnetic exchange is expected to be of RKKY-type.

show abstract

Atomic long-range order effects on Curie temperature and adiabatic spin-wave dynamics in strained Fe-Co alloy films

Cited by 2 publications

References 50 publications

Coulomb correlations and magnetic properties of L10 FeCo: A DFT+DMFT study

Coulomb correlations and magnetic properties of L10 FeCo: A DFT+DMFT study

Coulomb correlations and magnetic properties of L1$_0$ FeCo: a DFT+DMFT study

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