Effect of Barium Doping on Structure and Dielectric Properties of Bi_1.5ZnNb_1.5O₇ Ceramics

Bi_1.5-xBa_xZnNb_1.5O₇(x=0.05, 0.10, 0.15, 0.20, molar ratio) ceramics were prepared by solid sintering method. The effects of barium doping on sintering property, structure and dielectric property of the ceramics were studied. The results show that the sintering temperature of the ceramics decreased from 1 050℃ to 960℃ after barium doping. The phase of the ceramics was composed of single pyrochlorite, and its diffraction peak shifted to a small angular direction as the doping amount of barium increased. The dielectric constant and dielectric loss of the ceramics increased with increasing barium doping amount. Under different frequencies, the ceramics with different barium doping amount showed dielectric relaxation at low temperatures. The dielectric relaxation peak became widening and flattening with increasing barium doping amount, and shifted to high temperature directions. With increasing barium doping amount, the dielectric relaxation degree of the ceramics decreased first and then increased, and the relaxation activation energy and temperature coefficient increased first and then decreased.