The body-centered-tetragonal antiferromagnet EuGa4 exhibits A-type antiferromagnetic order below its N\'eel temperature TN=16.4 K in magnetic field H=0 where the moments are ferromagnetically aligned in the ab-plane with the Eu moments in adjacent Eu planes aligned antiferromagnetically. Previous magnetization versus field Mab(H) measurements revealed that the moments exhibit a spin-reorientation transition at a critical field Hc1 where the Eu moments become perpendicular to an in-plane magnetic field while still remaining in the ab plane. A theory for T=0 K was previously presented that successfully explained the observed low-field moment-reorientation behavior at T=2 K. Here we present a theory explaining the observed T dependence of Mab(H,T<TN) in the [1,0,0] direction for H≤Hc1(T) from 2 to 14 K arising from a T-dependent anisotropy energy.
@article{arxiv.2303.10673,
title = {Temperature-dependent Eu spin reorientations in the tetragonal A-type antiferromagnet EuGa$_4$ induced by small ab-plane magnetic fields},
author = {Santanu Pakhira and David C. Johnston},
journal= {arXiv preprint arXiv:2303.10673},
year = {2023}
}