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arXiv · 2601.15833

Magnetoelastic coupling at the field-induced transition in EuAl$_{12}$O$_{19}$

T. Haidamak·G. Bastien·P. Proschek·A. Eliáš·R. H. Colman·D. Gorbunov·S. Zherlitsyn·A. A. Zvyagin·G. A. Zvyagina·J. Prokleška·V. Sechovský·M. Vališka
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Abstract

Magnetoelastic coupling plays a crucial role in magnetic-field-induced transitions in anisotropic ferromagnets. Ultrasonic methods are suitable for experimental investigations of these phenomena. We investigate elastic constants in EuAl$_{12}$O$_{19}$, a quasi-two-dimensional anisotropic ferromagnet, by measuring sound velocity in magnetic fields perpendicular to spontaneous magnetization. The shear modulus $C_{44}$ exhibits dramatic softening at the field-induced transition from the ferromagnetic to a paramagnetic phase with magnetic moments forced to polarize along the applied transverse field. The softening is attributed to strong magnetic fluctuations near a second-order phase transition. Theoretical calculations based on magnetization data qualitatively reproduced the observed behavior within a strain-exchange mechanism. These results demonstrate that magnetoelastic coupling in EuAl$_{12}$O$_{19}$ arises primarily from exchange striction and provide a framework for modeling similar transitions in other anisotropic ferromagnets.

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T. Haidamak, G. Bastien, P. Proschek, A. Eliáš, R. H. Colman, D. Gorbunov, S. Zherlitsyn, A. A. Zvyagin, G. A. Zvyagina, J. Prokleška, V. Sechovský, M. Vališka. 2026-01-22. Magnetoelastic coupling at the field-induced transition in EuAl$_{12}$O$_{19}$. https://doi.org/10.1103/3pgp-l8kd

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