First-principles study of isotropic exchange interactions and spin stiffness in FeGe

•Calculated isotropic exchange interactions in FeGe are of RKKY type.•The mean-field magnetic transition temperature agrees with the experimental value.•The spin stiffness of FeGe is estimated using the Green’s function approach. We theoretically study the magnetic properties of iron germanium, know...

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Bibliographic Details
Published in:Journal of magnetism and magnetic materials 2018-12, Vol.467, p.58-63
Main Authors: Kashin, Ilya V., Andreev, Sergei N., Mazurenko, Vladimir V.
Format: Article
Language:English
Subjects:
Anisotropy
Exchange interactions
Exchanging
FeGe
First principles
Helimagnets
Iron
Magnetic fields
Magnetic properties
Magnetic transitions
Mathematical models
Micromagnetic model
Numerical analysis
Spin stiffness
Spin wave
Stiffness
Transition temperature
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Summary:•Calculated isotropic exchange interactions in FeGe are of RKKY type.•The mean-field magnetic transition temperature agrees with the experimental value.•The spin stiffness of FeGe is estimated using the Green’s function approach. We theoretically study the magnetic properties of iron germanium, known as one of canonical helimagnets. For this purpose we use the real-space spin Hamiltonian and micromagnetic model, derived in terms of Andersen’s “local force theorem”, to describe the low-lying magnetic excitations via spin-polarized Green’s function, obtained from the first-principles calculations. The model was designed to numerically evaluate the spin stiffness constant in reciprocal space, in order for assessment of the contributing itinerant mechanisms. The calculated pairwise exchange interactions reveal the essentiality of Ruderman-Kittel-Kasuya-Yosida coupling in FeGe. Thus provided mean-field estimation of magnetic transition temperature agrees good with the experimental measurement, underlining the necessity of the comprehensive real/reciprocal space-based approach for a proper description of magnetic excitations in FeGe.
ISSN:0304-8853
1873-4766
DOI:10.1016/j.jmmm.2018.07.032