New approach for designing bulk multiferroic composites made of two perovskite oxides with enhanced direct magnetoelectric coupling

The scarcity of single-phase magnetoelectric multiferroics has motivated active research towards the design of composites where polarization and magnetization are coupled through elastic strain at their interfaces. Up to now, most of bulk multiferroic composites are made of immiscible constituents that thus suffer from weak interface connectivity between them. Here, we propose an approach for designing particulate composites with constituents of perovskite ABO₃ structure that exhibit solid solubility, by acting on the lowering of the sintering temperature. We show that a BiFe_0.95Co_0.05O₃–PbZr_0.52Ti_0.48O₃ multiferroic composite with improved magnetoelectric coupling can be formed before a solid solution is reached. A Bi-rich interface promotes elastic strain transfer between the two constituents resulting in twice stronger direct magnetoelectric coefficient compared to pure BiFe_0.95Co_0.05O₃. These findings provide an easy and effective strategy for producing upgraded and original multiferroic composites made of constituents with the perovskite structure, known to host a wide variety of functionalities.