Multiferroic and magnetoelectric properties of BiFeO3/Bi4Ti3O12 bilayer composite films

• BiFeO3/Bi4Ti3O12 films exhibit well-defined multiferroic properties.
• BiFeO3/Bi4Ti3O12 films possess strong magnetoelectric effect.
• Clear domain structures and their switching were observed.

Multiferroic BiFeO3/Bi4Ti3O12 bilayer films were prepared using chemical solution deposition. Well-defined interfaces between BiFeO3 and Bi4Ti3O12 layers and clear domain structures were observed. The ferroelectric, leakage, dielectric, piezoelectric, magnetic as well as magnetoelectric properties were investigated for the composite films. It is shown that the composite films not only exhibit ferromagnetic and ferroelectric properties, but also possess strong magnetoelectric effect at room temperature. Thus outstanding magnetoelectric properties are attributed to the excellent coupling effect between BiFeO3 and Bi4Ti3O12 layers, which leads to a strong coupling interaction between ferromagnetic and ferroelectric orders. The present work provides a feasible way of preparing magnetoelectric composite films and facilitating their applications in micro-electro-mechanical system and information storage devices.