Room temperature multiferroicity and magnetoelectric coupling in Na-deficient sodium bismuth titanate

Abstract

Herein, we report a Na deficient single phase sodium bismuth titanate perovskite exhibiting ferromagnetism with reduced leakage conductivity and a self-biased high magnetoelectric (ME) coupling coefficient at room temperature (27 °C). Observed ferromagnetism is induced by sodium cation vacancy dominated by spin polarization of holes in the valence band. An unexpected high ME coupling coefficient of about 4.18 mV/cm Oe, observed at zero DC magnetic bias field, is relatively large and juxtapose to other single phase multiferroics including BiFeO3. This study opens up an altered strategy in designing multiferroic materials with reinforced ME coupling at room temperature.