Effect of different ionic valence state doping on the structure and characteristic of BiFeO ₃ ‐BaTiO ₃ ‐based ceramics

Abstract 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.