Structural evolution and enhanced multiferroicity in BiFeO3-based ceramics via rare earth element co-substitution

In this study, multiple rare earth elements were introduced to modify the multiferroic properties of BiFeO 3 . The effects of co-substitution on the structural evolution and properties were thoroughly investigated. With increasing substitution content, the ceramics underwent a symmetry transition from R 3 c to Pna 2 1 and finally to Pbnm . Co-substitution significantly enhanced the ferroelectric properties, with the highest remanent polarization of 33.14 μC/cm² observed at x = 0.10. Due to the symmetry evolution, ferromagnetism was released from the cycloidal spin structure, and the hysteresis loop gradually saturated, with the highest remanent magnetization ( M r ) of 0.25 emu/g observed at x = 0.16. The concurrent improvement in ferroelectricity and ferromagnetism resulted in substantial magnetoelectric coupling performance, with α ME = 3.50 mV/(cm·Oe). Moreover, direct current poling significantly induced the reverse transition from R 3 c to Pna 2 1 , indicating the potential for electrically controlled magnetism. This study provides a new perspective for modifying the magnetoelectric properties of BiFeO 3 .