Electric field dependences of optical activity and birefringence of Pb
0.92La0.08(Zr0.7Ti0.3)(0.98)O-3(PLZT(8/70/30)) were studied using the
high-accuracy universal polarimeter (HAUP) method in a temperature reg
ion between 0 degrees C and 90 degrees C. PLZT(8/70/30) was optically
active in the low-temperature and inactive in the high-temperature pha
ses. Furthermore it was revealed that gyration and birefringence in th
e low-temperature phase manifested typical butterfly hysteresis loops
with respect to electric fields. From analysis of Weissenberg photogra
phs, the ceramics of both high- and low-temperature phases were found
to consist of crystallites which were distributed in equal weight alon
g the total solid angles. Using the combined evidence from HAUP and X-
ray methods, it was clarified that the classes of the high- and low-te
mperature phases are T-h and C-3, respectively.