Symmetry evolution and modulation of multiferroic characteristics in Bi1−xLaxFeO3 ceramics

Abstract

The substitution of rare-earth ions has been recognized as an effective way to modify the multiferroic properties, especially to realize the electric field-controlled magnetism in BiFeO3 ceramics, in which the symmetry modulation of R3 c/ Pna21 and the unlocked ferromagnetism through breaking the cycloidal spin structure are the key issues. Here, the enhancement of ferroelectric polarization and weak ferromagnetism are investigated in Bi1− xLa xFeO3 ceramics together with the magnetoelectric coupling coefficient αME with the development of the Pna21 phase. The expected electric field-controlled magnetism is achieved at the phase boundary through the electric field-induced transition of Pna21/ R3 c, where the variation of magnetization reaches 34.18 emu/mol (58.95%) at x =  0.18 after poling.