A three-sublattice mean-field approximation (MFA) to ferroelectromagnets with coexisting antiferromagnetic order and ferroelectric order is proposed to understand the magnetic transitions induced by magnetoelectric coupling between the two types of orders. The temperature dependence of magnetization, magnetic susceptibility and magnetoelectric susceptibility under different coupling strengths are calculated, indicating the intrinsic weak ferromagnetic transition at low temperature due to the magnetoelectric coupling. Comparing with the predictions given by earlier MFA, the present MFA predictions are in better accord with the Monte Carlo simulations.
部门归属
nanjing univ, solid state microstruct lab, nanjing 210093, peoples r china. chinese acad sci, int ctr mat phys, shenyang, peoples r china.;liu, jm (reprint author), nanjing univ, solid state microstruct lab, nanjing 210093, peoples r china;liujm@nju.edu.cn
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