Effect of tuning A/B substitutions on multiferroic characteristics of BiFeO3-based ternary system ceramics

Abstract

BiFeO3 is the most important type-I multiferroics, with a different origin of ferroelectricity (Bi-site) and magnetism orders (Fe-site). However, the magnetoelectric coupling effect is poor due to the huge differential between ferroelectric Curie temperature TC and Néel temperature TN. In this work, the crystal structure, ferroelectric and magnetic properties of BiFeO3-based ceramics were investigated by tuning the substitution amount of A and B sites. The XRD and Raman analyses confirmed the phase transformation from polar rhombohedral R3c to non-polar orthorhombic Pbnm with increasing substitution amount of A-site. DSC analysis indicated that the Curie temperature TC decreased linearly with increasing A-site substituted content, and the magnetic transition temperature TN decreased linearly with increasing B-site substituted content. Meanwhile, for BF008-01 sample, the obviously thermal hysteresis observed in DSC curves indicated the first-order ferroelectric transition. For other samples, the Curie temperature was hard to detect due to the relaxor ferroelectric characteristics. The ferroelectric properties obtained by PUND method indicated the enhanced ferroelectricity, which can be attributed to the decreased leakage current. The magnetic properties were improved, and the maximum remnant magnetization Mr was obtained at BF008-01 sample, where Mr = 75.4 emu/mol. The magnetic properties are mainly affected by the substitution content of B site and the structure of BiFeO3-based ceramics. This work realized the precise regulation of TC and TN of BiFeO3-based ceramics.