Electric-field-controlled magnetism due to field-induced transition of Pna21/R3c in Bi1-xGdxFeO3 ceramics

BiFeO3 has been recognized as one of the most important room-temperature single-phase multiferroic materials, but it still suffers from several drawbacks especially the weak magnetoelectric coupling. In the present work, the electric-field-controlled magnetism is achieved in Bi1-xGdxFeO3 system, which involves a field-induced transition of Pna21/R3c at the morphotropic phase boundary region, and the magnetic state is switched between cycloidal state and canted antiferromagnetic state. The electric-field-controlled magnetism becomes reversible with the help of annealing, which is confirmed by magnetic hysteresis loops and the quantitative ratio of the involved phases for the as-sintered, as-poled and as-annealed samples. Compared with the systems of Bi1-xNdxFeO3 and Bi1-xSmxFeO3, it is easier to tune the symmetry from R3c to Pna21 with lower rare earth-content, and the field-induced transition is more apparent and subsequently leads to more significant electric-field-controlled magnetism in a wider composition range.