Rainbow ceramics: Processing techniques; piezoelectric, dielectric and pyroelectric properties; and polarization distributions as determined with SLIMM

Rainbow ceramics are stress-biased, dome-shaped, electromechanical benders. Two PLZT compositions were examined. Previous studies have shown that their piezoelectric properties vary significantly in the lateral direction and the chemical variation in the thickness direction would be expected to influence properties in that direction as well. The Surface Laser Intensity Modulation Method (SLIMM) was used for determination of the polarization distribution in the thickness direction at a number of different lateral locations. Piezoelectric d₃₃, capacitance, dielectric loss, displacement and pyroelectric measurements were also made. The raw SLIMM data showed numerous peaks produced by the piezoelectric effect at mechanical resonances. The calculated polarization distributions were extremely nonuniform. The primary pyroelectric coefficient was the dominant component of the total pyroelectric effect in the low-La composition, and the secondary coefficient was dominant in the high-La composition.