Multiferroic properties and magnetoelectric coupling in Fe/Co co-doped Bi3.25La0.75Ti3O12 ceramics

Abstract

Polycrystalline Bi_3.25La_0.75(Ti_3−xFe_x/2Co_x/2)O₁₂ (0 ≤ x ≤ 0.5) ceramics are synthesized by the conventional solid state reaction method. Good ferroelectricity and weak ferromagnetism are obtained simultaneously at room temperature when x ≥ 0.2. The ceramics with x = 0.25 possess the best comprehensive properties, including high phase purity, large ferroelectric polarization, great dielectric constant, and also, larger remnant magnetization compared with other samples. Furthermore, significant dielectric anomalies appear near both the ferromagnetic Curie temperature and the spin glass freezing temperature. The possible magnetoelectric coupling mechanism is considered to be the associated binding effect of magnetic interaction on the migration of charged defects, especially oxygen vacancies.