Enhanced dielectric and ferroelectric properties of Ba and Ti co-doped BiFeO_3 multiferroic ceramics

摘要

Multiferroic ceramics Bi_(0.5)Ba_(0.2)Fe_(1-x)Ti_xO_3 with x = 0,0.1 and 0.2 were prepared by using the conventional solid state reaction method. The structural, dielectric, ferroelectric and magnetic properties were investigated. The structure phase transition from rhombohedral to tetragonal with increasing the Ti substitution concentration was confirmed using X-ray diffraction. The reduction of low frequency dispersion in the dielectric constant and loss with an increase in the Ti content was observed. The ferroelectric measurements revealed that the leakage current is significantly suppressed with Ti substitution. Magnetic hysteresis loops showed a continuous decrease in magnetization with Ti substitution, which can be attributed to the collinear antiferromagnetic spin structure in tetragonal structure. In addition, a remarkable change in the polarization and ferroelectric loop area after poling the samples in the dc magnetic field indicates the presence of magnetoelectric coupling at room temperature.