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 La0.03Sr0.255B a0.7Nb2-yTiyO(6-y)/2 (LSBNT) ceramic system were studied for different Nb/T i concentrations. For dielectric hysteresis measurements at room temperatur e, the remanent polarization increases and the: coercive field decreases wi th titanium concentration for an applied electric field of 20 kV/cm. The th ermally stimulated current measurements show the pyroelectric peak for all compositions while a second smaller peak at higher temperature, possibly as sociated with induced vacancy-impurity dipoles, is also observed in all cas es. The second peak contribution was mathematically eliminated to determine the remanent polarization and pyroelectric coefficient, both associated on ly with permanent ferroelectric dipoles. In this case, the remanent polariz ation decreased with the rise in titanium concentration. The La0.03Sr0.255B a0.7Nb1.95Ti0.05O5.975 sample, in particular, has excellent pyroelectric re sponse, making this material very suitable for pyroelectricity-derived appl ications. (C) 2000 Elsevier Science Ltd. All rights reserved.