PIEZOELECTRIC PROPERTIES AND EQUIVALENT-CIRCUITS OF FERROELECTRIC RELAXOR SINGLE-CRYSTALS

Temperature dependent piezoelectric properties of ferroelectric relaxe r single crystals, particularly the Ce-doped strontium barium niobate Sr0.6Ba0.4Nb2O6:Ce (SBN60:Ce) crystals, were investigated by resonance and anti-resonance technique. Characteristic resonant frequencies (f( r)-f(a), f(s)-fp, and f(m)-f(n)) were studied using equivalent circuit simulation. The piezoelectric resonance in a ferroelectric relaxer SB N60:Ce resonator was found to persist into temperatures much higher th an T-m (temperature at which dielectric constant kappa has a maximum a t 1kHz), in contrast to a normal ferroelectric resonator such as TGS. The parameters in an equivalent circuit, however, are phenomenally dif ferent from that of a normal resonator like TGS, at near and above the transition temperature region. Experimental results pertaining to und erstanding the piezoelectric resonance characteristics in ferroelectri c relaxers are reported.