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

Abstract

BiFeO3‐BaTiO3‐based ceramics are promising multiferroic materials for a wide range of applications. In this paper, the effects of different ionic valence state((Ga0.5Ta0.5)4+, Ta5+) doping on the structure and properties of 0.73BiFeO3‐0.27BaTi1‐y(Ga1‐xTax)yO3 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 Mr = .13 emu/g. According to relevant analysis, high‐valence element substitution can enhance the magnetic properties and reduce the coercive field of BiFeO3, 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 BiFeO3 ceramics.