Structural and multiferroic properties of epitaxial γ-Fe2O3–BiFeO3/Bi3.25La0.75 Ti3O12 composite bi-layers

Multiferroic properties of γ-Fe2O3–BiFeO3/Bi3.25La0.75Ti3O12 epitaxial composite bi-layers grown on SrRuO3/SrTiO3(1 1 1) are compared with the properties of single phase BiFeO3 and Bi3.25La0.75Ti3O12 thin films. The composite bi-layers show well-saturated hysteresis loops with a low coercive field, a high fatigue resistance and high saturation magnetization. The insulating Bi3.25La0.75Ti3O12 underlayer reduces significantly both the leakage current and the coercive field of the heterostructure (200 kV cm−1) at the expense of a lower polarization (20 µC cm−2), while the epitaxial γ-Fe2O3 secondary phase that develops within the relaxed epitaxial BiFeO3 matrix allowed for a high saturation magnetization.