Enhanced ferroelectric and ferromagnetic properties in lead-free multilayer composite films based on ferroelectric (Bi_0.5Na_0.5)_0.945Ba_0.055TiO₃ and multiferroic BiFeO₃

The study of the functional properties of the multilayer composite films of ferroelectric (Bi_0.5Na_0.5)_0.945Ba_0.055TiO₃ (BNBT) and multiferroic BiFeO₃ (BF) obtained by chemical solution deposition has been performed in this work. First, it has been observed a significant improvement of the remnant polarization of the multilayer composite with respect to the single phase film of BNBT: P_r = 32 μC × cm⁻², which is comparable with the values reported for bulk BNBT. This is a consequence of the stabilization of the ferroelectric domains of BNBT, although the relaxor character is still present. The leakage currents, which prevent the full exploitation of the properties of BF films, are reduced thanks to the combination with insulator BNBT layers. Besides, the magnetic behavior shows values of remnant magnetization at room temperature that makes this multilayer composites promising for multiferroic applications.