Significant enhancements of dielectric and magnetic properties in Bi(Fe_1−<i>x</i>Mg_<i>x</i>)O_{3−<i>x</i>/2}induced by oxygen vacancies

Abstract

Bi(Fe1−xMgx)O3−x/2 (x = 0–10%) ceramics were synthesized by high-energy ball milling and solid-state reaction. It was found that a small amount of Mg doping leads to a dramatic enhancement in dielectric permittivity (∼two orders of magnitude), along with an apparent improvement in ferromagnetism. The observed significant enhanced dielectric properties may be interpreted by the Maxwell–Wagner relaxation in association with internal barrier layer capacitance. The ferromagnetism can be ascribed to the creation of unbalanced Fe3+ spins and relative long-range coupling mediated by the oxygen vacancies trapped localized electrons.