IMPURITY DOPING EFFECT ON PIEZOELECTRICIT Y AND STRAIN-INDUCED BY ELECTRIC-FIELD IN PIEZOELECTRIC CERAMICS

The effects of impurities on piezoelectric constant and the strain cha racteristics were investigated for ceramics with the composition of (P b0.95Sr0.05) (Zr0.54Ti0.46)O-3. The piezoelectric constant d(31) of sa mples doped with Nb and W was larger than that of non-doped samples, a nd d(31) Of samples doped with Fe and Ni was smaller than that of non- doped samples, It was found that the actually found strain (delta) und er high DC electric held was larger for donor doping and smaller for a cceptor doping, In all samples, the delta values were larger than the calculated strain (delta(cal)) obtained by multiplying d(31) by DC ele ctric held. This result suggested that the strain (delta(p)) of domain orientation due to electric held exists, The delta(p) values of sampl es doped with donor were larger than that of non-doped samples, and th ose of samples with acceptor were smaller than that of non-doped sampl es, We found that delta(p) is related to the binding force of domain, and that the binding force of domain is dependent on the internal held of space charge produced by dopants.