Magnetization, excitations, and microwave power absorption in transition-metal/rare-earth ferrimagnets with disorder

Fuente: arXiv
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Main Authors: Garanin, D. A., Chudnovsky, E. M.
Format: Preprint
Published: 2025
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author Garanin, D. A.
Chudnovsky, E. M.
author_facet Garanin, D. A.
Chudnovsky, E. M.
contents Efficient numerical routines are developed for numerical studies of the dependence of the equilibrium magnetic states, excitations, and microwave power absorption on temperature and composition in transition-metal/rare-earth ferrites, including the reversal of the Néel vector occurring on both temperature and the concentration of the rare-earth atoms. It results in a drastic change in the behavior at the magnetization and angular-momentum compensation points. Dominant uniform oscillation modes are obtained by computing the magnetization correlation function. They are compared with the analytical solution, which is analyzed in detail. The fluctuation-dissipation theorem is used to compute the frequency dependence of the absorbed microwave power. A good agreement with analytical results is demonstrated. Disorder caused by random positions of rare-earth atoms in a diluted RE system leads to multiple localized modes that converge into broad absorption maxima as the size of the system increases. The power absorption integrated over frequency exhibits a minimum at the compensation point.
format Preprint
id arxiv_https___arxiv_org_abs_2510_14237
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Magnetization, excitations, and microwave power absorption in transition-metal/rare-earth ferrimagnets with disorder
Garanin, D. A.
Chudnovsky, E. M.
Materials Science
Efficient numerical routines are developed for numerical studies of the dependence of the equilibrium magnetic states, excitations, and microwave power absorption on temperature and composition in transition-metal/rare-earth ferrites, including the reversal of the Néel vector occurring on both temperature and the concentration of the rare-earth atoms. It results in a drastic change in the behavior at the magnetization and angular-momentum compensation points. Dominant uniform oscillation modes are obtained by computing the magnetization correlation function. They are compared with the analytical solution, which is analyzed in detail. The fluctuation-dissipation theorem is used to compute the frequency dependence of the absorbed microwave power. A good agreement with analytical results is demonstrated. Disorder caused by random positions of rare-earth atoms in a diluted RE system leads to multiple localized modes that converge into broad absorption maxima as the size of the system increases. The power absorption integrated over frequency exhibits a minimum at the compensation point.
title Magnetization, excitations, and microwave power absorption in transition-metal/rare-earth ferrimagnets with disorder
topic Materials Science
url https://arxiv.org/abs/2510.14237