Significant enhancements of dielectric and magnetic properties in Bi(Fe1-xMgx)O3-x/2 induced by oxygen vacancies

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 (similar to 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.