Magnetization and exchange-stiffness constants of Fe-Al-Si alloys at finite-temperatures: A first-principles study

Fuente: arXiv
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Autores principales: Yamashita, Shogo, Sakuma, Akimasa
Formato: Preprint
Publicado: 2024
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author Yamashita, Shogo
Sakuma, Akimasa
author_facet Yamashita, Shogo
Sakuma, Akimasa
contents We investigated the magnetic properties of Sendust (Fe-Al-Si) alloys not only at 0 K but also at finite-temperatures by means of the first-principles calculations assuming A2, B2, and DO3 structures. We confirmed that the itinerant characteristics of 3d electrons of Fe are not negligible for A2 and B2 structures and a significantly small exchange stiffness constant exists at zero-temperature in a B2 structure. However, the calculated Curie temperatures are in the same order for all structures; this indicates that the Curie temperature cannot be determined only by the exchange interactions at zero-temperature in itinerant electron systems. Temperature dependence of the exchange interaction, namely spin configuration dependence, also might be important for determining it. In addition, this property might also be related to the unique behavior of the temperature dependence of the exchange stiffness constant for the B2 structure, which does not decrease monotonically as temperatures increase, contrary to the behavior expected from the Heisenberg model. In addition, we investigated composition dependence on the exchange stiffness constant at zero-temperature and confirmed that the substitution of Si with Al could improve the amplitude of the exchange stiffness constant at zero-temperature for all structures.
format Preprint
id arxiv_https___arxiv_org_abs_2403_14096
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Magnetization and exchange-stiffness constants of Fe-Al-Si alloys at finite-temperatures: A first-principles study
Yamashita, Shogo
Sakuma, Akimasa
Materials Science
We investigated the magnetic properties of Sendust (Fe-Al-Si) alloys not only at 0 K but also at finite-temperatures by means of the first-principles calculations assuming A2, B2, and DO3 structures. We confirmed that the itinerant characteristics of 3d electrons of Fe are not negligible for A2 and B2 structures and a significantly small exchange stiffness constant exists at zero-temperature in a B2 structure. However, the calculated Curie temperatures are in the same order for all structures; this indicates that the Curie temperature cannot be determined only by the exchange interactions at zero-temperature in itinerant electron systems. Temperature dependence of the exchange interaction, namely spin configuration dependence, also might be important for determining it. In addition, this property might also be related to the unique behavior of the temperature dependence of the exchange stiffness constant for the B2 structure, which does not decrease monotonically as temperatures increase, contrary to the behavior expected from the Heisenberg model. In addition, we investigated composition dependence on the exchange stiffness constant at zero-temperature and confirmed that the substitution of Si with Al could improve the amplitude of the exchange stiffness constant at zero-temperature for all structures.
title Magnetization and exchange-stiffness constants of Fe-Al-Si alloys at finite-temperatures: A first-principles study
topic Materials Science
url https://arxiv.org/abs/2403.14096