First-principles study of exchange coupling constants in Nd\(_x\)Fe\(_{1-x}\) amorphous alloy

We investigate the exchange coupling constant \(J_{ij}\) in Nd\(_x\)Fe\(_{1-x}\) amorphous alloys with different compositions within the framework of first-principles calculation. We observed a strong atomic-dependence of \(J_{ij}\) and its fluctuations. We show that the composition strongly affects...

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Bibliographic Details
Published inarXiv.org
Main Authors Terasawa, Asako, Gohda, Yoshihiro
Format Paper
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 18.08.2020
Subjects
Amorphous alloys
Atomic properties
Composition
Coordination numbers
Couplings
Dependence
Exchanging
First principles
Mathematical analysis
Metallic glasses
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Summary:We investigate the exchange coupling constant \(J_{ij}\) in Nd\(_x\)Fe\(_{1-x}\) amorphous alloys with different compositions within the framework of first-principles calculation. We observed a strong atomic-dependence of \(J_{ij}\) and its fluctuations. We show that the composition strongly affects the distance dependence of \(J_{ij}\). Composition dependence of calculated Curie temperatures is modest for \(x<0.5\). To examine the effect of the local environment on the exchange couplings, we demonstrate combined analyses of the coordination structure and exchange coupling constants using the Gabriel graph. Our study reveals that the Curie temperatures are mostly dominated by the averaged \(J_{ij}\) and coordination numbers determined by the pairs of neighboring atoms. We also observed that the exchange couplings between Fe--Fe and Fe--Nd become stronger with increasing the number of surrounding Nd atoms.
ISSN:2331-8422