Pair anisotropy in disordered magnetic systems

Fuente: arXiv
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Main Authors: Das, K., Szwacki, N. Gonzalez, Gas, K., Sawicki, M., Hayn, R., Sztenkiel, D.
Format: Preprint
Published: 2024
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_version_ 1866913146810138624
author Das, K.
Szwacki, N. Gonzalez
Gas, K.
Sawicki, M.
Hayn, R.
Sztenkiel, D.
author_facet Das, K.
Szwacki, N. Gonzalez
Gas, K.
Sawicki, M.
Hayn, R.
Sztenkiel, D.
contents Accurate modelling of magnetism is pivotal for elucidating the microscopic origins of magnetic phenomena in functional materials. However, for a specified class of materials, such as random dilute ferromagnets or alloys, the reliance on simplifying assumptions, such as single-ion anisotropy, limits the accuracy of existing spin models. In such systems, there is a significant probability of the formation of nearest-neighbor magnetic ion pairs or higher order clusters, whose presence breaks the local symmetry of otherwise isolated magnetic species. Here, we introduce the concept of pair-induced uniaxial anisotropy and demonstrate how nearby atoms influence each other's anisotropic behavior. This effect is investigated in the dilute magnetic semiconductor Ga$_{1-x}$Mn$_x$N, by means of density functional theory calculations. The inclusion of pair anisotropy in the atomistic spin simulations significantly improves the agreement between simulated and experimental magnetization curves, in contrast to models that consider only single-ion anisotropy.
format Preprint
id arxiv_https___arxiv_org_abs_2410_22035
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Pair anisotropy in disordered magnetic systems
Das, K.
Szwacki, N. Gonzalez
Gas, K.
Sawicki, M.
Hayn, R.
Sztenkiel, D.
Materials Science
Accurate modelling of magnetism is pivotal for elucidating the microscopic origins of magnetic phenomena in functional materials. However, for a specified class of materials, such as random dilute ferromagnets or alloys, the reliance on simplifying assumptions, such as single-ion anisotropy, limits the accuracy of existing spin models. In such systems, there is a significant probability of the formation of nearest-neighbor magnetic ion pairs or higher order clusters, whose presence breaks the local symmetry of otherwise isolated magnetic species. Here, we introduce the concept of pair-induced uniaxial anisotropy and demonstrate how nearby atoms influence each other's anisotropic behavior. This effect is investigated in the dilute magnetic semiconductor Ga$_{1-x}$Mn$_x$N, by means of density functional theory calculations. The inclusion of pair anisotropy in the atomistic spin simulations significantly improves the agreement between simulated and experimental magnetization curves, in contrast to models that consider only single-ion anisotropy.
title Pair anisotropy in disordered magnetic systems
topic Materials Science
url https://arxiv.org/abs/2410.22035