Structural transition and magnetic properties of Mn doped BiSmFeO ceramics.

We investigated the effects of Mn doping on the crystal structure, phonon vibration, and magnetic properties of BiSmFeO ceramics. Mn doping effectively modified the rhombohedral symmetry and induced a structural transition from an 3 rhombohedral to orthorhombic structure. Magnetic measurements revealed a weak ferromagnetic behavior, which was related to the canted antiferromagnetic order of the structure. The cycloidal spin structure of the 3 phase could not be suppressed by substitution of Mn at the Fe site. Studies on the self-phase transition and electric field-induced structural transition revealed many changes in coercivity and remanent magnetization, which are believed to originate from the 3/ phase switching along with spin frustration. Observations of the field step-dependent hysteresis loop and the ferromagnetic-like hysteresis loop after poling in an electric field provided direct evidence of phase boundary (PB) ferromagnetism and magnetic coupling at the PB.