Effect of different ionic valence state doping on the structure and characteristic of BiFeO3-BaTiO3-based ceramics

BiFeO 3 -BaTiO 3 -based ceramics are promising multiferroic materials for a wide range of applications. In this paper, the effects of different ionic valence state((Ga 0.5 Ta 0.5 ) 4+ , Ta 5+ ) doping on the structure and properties of 0.73BiFeO 3 -0.27BaTi 1- y (Ga 1- x Ta x ) y O 3 ceramics were investigated. X-ray diffraction analysis showed that all samples were determined by rhombohedral R3c phase and tetragonal P4mm phase. A frequency-independent dielectric anomaly with obvious thermal hysteresis was detected in all samples, indicating the first-order ferroelectric phase transition, and the Curie temperatures were all above 600°C. The ferroelectric analysis found that the doping of donor element Ta reduced the coercive field, with a slight decrease of remanent polarization, which can be attributed to the soft effect of Ta element. Meanwhile, the magnetic properties were enhanced for all samples, with a maximum in 15T ( x = 1, y = .015) sample, where M r = .13 emu/g. According to relevant analysis, high-valence element substitution can enhance the magnetic properties and reduce the coercive field of BiFeO 3 , while low-valence element substitution can reduce dielectric loss. This result points out a way for us to choose appropriate doping elements to improve the performance of BiFeO 3 ceramics.