Micromagnetic Study of the Dipolar-Exchange Spin Waves in Antiferromagnetic Thin Films

Fuente: arXiv
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Main Authors: Wang, Jiongjie, Xiao, Jiang
Format: Preprint
Published: 2025
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author Wang, Jiongjie
Xiao, Jiang
author_facet Wang, Jiongjie
Xiao, Jiang
contents In antiferromagnets, dipolar coupling is often disregarded due to the cancellation of magnetic moments between the two sublattices, leaving spin-wave dispersion predominantly determined by exchange interactions. However, antiferromagnetic spin waves typically involve a slight misalignment of the magnetic moments on the sublattices, giving rise to a small net magnetization that enables long-range dipolar coupling. In this paper, we investigate the role of this dipolar coupling in spin-wave excitations and its influence on the spin-wave dispersion. Our findings show that: (i) when the Néel vector is perpendicular to the film plane or lies within the film plane and parallel to the wave vector, the dispersion branches can be divided into two groups -- those unaffected by the dipolar field and those influenced by it. In these cases, the total magnetic moment remains linearly polarized, but the polarization directions differ between the two types of branches; (ii) when the Néel vector lies in the film plane and is perpendicular to the wave vector, the dipolar interactions affect both types of dispersion branches, leading to their hybridization. This hybridization alters the polarization of the magnetic moment, resulting in elliptical polarization.
format Preprint
id arxiv_https___arxiv_org_abs_2505_13970
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Micromagnetic Study of the Dipolar-Exchange Spin Waves in Antiferromagnetic Thin Films
Wang, Jiongjie
Xiao, Jiang
Mesoscale and Nanoscale Physics
Materials Science
In antiferromagnets, dipolar coupling is often disregarded due to the cancellation of magnetic moments between the two sublattices, leaving spin-wave dispersion predominantly determined by exchange interactions. However, antiferromagnetic spin waves typically involve a slight misalignment of the magnetic moments on the sublattices, giving rise to a small net magnetization that enables long-range dipolar coupling. In this paper, we investigate the role of this dipolar coupling in spin-wave excitations and its influence on the spin-wave dispersion. Our findings show that: (i) when the Néel vector is perpendicular to the film plane or lies within the film plane and parallel to the wave vector, the dispersion branches can be divided into two groups -- those unaffected by the dipolar field and those influenced by it. In these cases, the total magnetic moment remains linearly polarized, but the polarization directions differ between the two types of branches; (ii) when the Néel vector lies in the film plane and is perpendicular to the wave vector, the dipolar interactions affect both types of dispersion branches, leading to their hybridization. This hybridization alters the polarization of the magnetic moment, resulting in elliptical polarization.
title Micromagnetic Study of the Dipolar-Exchange Spin Waves in Antiferromagnetic Thin Films
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2505.13970