Effects of Nd and high-valence Mn co-doping on the electrical and magnetic properties of multiferroic BiFeO3 ceramics

Pure BiFeO3 (BFO), 15% Nd doped BFO (BNF), and 15% Nd and 2% high-valence Mn co-doped BFO (BNFM) multiferroic ceramics were prepared by a rapid liquid phase sintering technique. A structural transition from rhombohedral R3cR3c to orthorhombic P4mmP4mm occurred in the BNF and BNFM ceramics. The co-doped BNFM ceramics exhibit the largest dielectric constant, the smallest dielectric loss and leakage current, and an improved rectangular-shaped polarization hysteresis loop with a remnant polarization as high as 31 μC/cm2, which could be attributed to the lower concentration of charge defects and the structural transition. Besides, enhanced ferromagnetism is confirmed in BNFM with a remnant magnetization of 0.075 emu/g and a coercive magnetic field of 5.8 kOe, which might be attributed to the effective suppression of the spatially modulated spin structure by the Nd and Mn co-doping.