Dielectric hysteresis and pyroelectricity in the La0.03Sr0.255Ba0.7Nb2-yTiyO(6-y)/2 ferroelectric ceramic system

The dielectric hysteresis and pyroelectric properties of the La0.03Sr0.255Ba0.7Nb2-yTiyO(6-y)/2 (LSBNT) ceramic system were studied for different Nb/Ti concentrations. For dielectric hysteresis measurements at room temperature, the remanent polarization increases and the: coercive field decreases with titanium concentration for an applied electric field of 20 kV/cm. The thermally stimulated current measurements show the pyroelectric peak for all compositions while a second smaller peak at higher temperature, possibly associated with induced vacancy-impurity dipoles, is also observed in all cases. The second peak contribution was mathematically eliminated to determine the remanent polarization and pyroelectric coefficient, both associated only with permanent ferroelectric dipoles. In this case, the remanent polarization decreased with the rise in titanium concentration. The La0.03Sr0.255Ba0.7Nb1.95Ti0.05O5.975 sample, in particular, has excellent pyroelectric response, making this material very suitable for pyroelectricity-derived applications. (C) 2000 Elsevier Science Ltd. All rights reserved