Effects of ion doping at different sites on electrical properties of ferroelectric Bi4Ti3O12 ceramics

Pure, La3+ doped at A site, V5+ doped at B site, and La3+ and V5+ co-doped ferroelectric Bi4Ti3O12 (BTO), Bi3.25La0.75Ti3O12 (BLT), Bi4Ti2.98V0.02O3 (BTV) and Bi3.25La0.75Ti2.98V0.02O12 (BLTV) were successfully prepared by conventional sintering technique. The structures of the ceramics were investigated by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. X-ray diffraction indicated that assemblages of all sintered ceramics consist of a single phase of Bi4Ti3O12, implying that the A-site La3+ and B-site V5+ substitutions in this case do not affect the layered structure. Among these ceramics, BLTV ceramic exhibited the best electrical properties. The leakage current density of BLTV ceramic was only 1.3 x 10(-4) Acm(-2) at 40 KVcm(-1), two orders of magnitude lower than BTO ceramic. Besides, a saturated ferroelectric hysteresis loops with largest remnant polarization 2Pr of 30.6 mu C/cm(2) was observed for this sample. These suggested that the co-doped Bi4Ti3O12 ceramic by La3+ and V5+ at A and B sites showed advantages in application over the pure BTO, doped BLT and BTV ceramic, respectively.