Remarkable Electric Field‐Controlled Magnetism in La/Sm Co‐Substituted BiFeO 3 Multiferroic Ceramics

ABSTRACT Rare earth (RE) substitution is the primary way to realize the electric field‐controlled magnetism in BiFeO 3 multiferroic ceramics by breaking the cycloidal spin structure to release the intrinsic weak ferromagnetism, where the electric field‐induced phase transition of Pna 2 1 /R 3 c plays the key role. In the present work, the remarkable electric field‐controlled magnetism has been achieved in La/Sm co‐substituted BiFeO 3 multiferroic ceramics. The structure evolution in Bi 1‐ x (La 0.37 Sm 0.63 ) x FeO 3 ceramics is modulated from R 3 c to Pna 2 1 and finally Pbnm with increasing x . The weak ferromagnetism is released as the symmetry is tuned from R 3 c to Pna 2 1 and the cycloidal spin structure is broken. Furthermore, La/Sm co‐substitution significantly suppresses the leakage current to a level far below that of other RE‐substituted BiFeO 3 ceramics, thereby facilitating the enhanced dielectric strength, which significantly promotes the electric field‐induced phase transition of Pna 2 1 /R 3 c , and subsequently, the remarkable electric field‐controlled magnetism (a change of M r up to 62.7%) is achieved in the present ceramics. Moreover, the significant improvement in ferroelectricity is also achieved after the electric field‐induced phase transition of Pna 2 1 /R 3 c .