Distribution of piezoelectric properties in Pb[(Mg1/3Nb2/3)0.7Ti0.3]O3 single crystal

Piezoelectric property distribution was investigated in a Pb[(Mg1/3Nb2/3)(0.7)Ti-0.3]O-3 single-crystal (001) wafer grown by the Bridgman technique. There are three visual areas in the crystal: opaque part, transparent part and dendritic part. The piezoelectric properties of the dendritic part were similar to those of the transparent part, and the electromechanical (c/m) coupling coefficient of the length mode, k(31) was 70.6% at -25degreesC and increased to its highest value of 84.6% at 68degreesC. The c/m coupling factors of the thickness mode k(t) (59-60%) were almost the same in the transparent part and opaque part at room temperature. However, there was a large difference in k(31) between the transparent part (k(31) = 76%) and the opaque part (k(31) = 51-60%). Therefore, k(31) measurement is a good tool for determining the quality and uniformity level of Pb[(Mg1/3Nb2/3)(1-x)Ti-x]O-3 single crystals.