Effect of Ti doping on the dielectric, ferroelectric and magnetic properties of Bi-0.86 La0.08Sm0.14FeO3 ceramics

By using solid states reaction method, Bi0.86La0.08Sm0.14Fe1-xTixO3 ceramics with different Ti4+ contents (x = 0, 0.01, 0.02, 0.04, 0.08, 0.12, 0.16, 0.20) were prepared. Effects of Ti doping content on the microstructure, conductive, dielectric, ferroelectric and magnetic properties were systematically studied. The Bi0.86La0.08Sm0.14Fe1-xTixO3 perovskite structure was confirmed by XRD patterns. SEM results revealed porous and homogeneous structure of specimens. Compared with other ceramics, the sample (x = 0.04) shows the lowest leakage current value, which is attributed to the relatively homogeneous surface morphology and less defects. The dielectric constant increases first and then descends with increasing Ti4+ concentration, this behavior maybe caused by the existence of oxygen vacancies. The maximal dielectric constant (similar to 2000 at 100 Hz) is obtained in the sample (x = 0.16), while the specimen (x = 0.02) presents the largest dielectric loss (similar to 28, at 100 Hz). The ceramics (x = 0.08) shows the best ferroelectric properties, the remnant polarization (P-r) is 1.4304 mu C/cm(2) and the coercive field (E-c) is 25.9 kV cm(-1) at the frequency of 3 kHz. The saturation magnetization (M-s) decreases with the increase of x, because the variation of Fe3+ can affect the domain structure. These results indicate that proper Ti4+ doping in B site can distinctly improve the multiferroic properties of BiFeO3 based ceramics, implying potentially practical applications in electronic devices.