THE PIEZOELECTRIC TENSOR ELEMENT D(33) OF KTIOPO4 DETERMINED BY SINGLE-CRYSTAL X-RAY-DIFFRACTION

The d(33) piezoelectric constant of KTiOPO4 (potassium titanium orthop hosphate, KTP) has been determined for two different samples and at te mperatures between 100 and 220 K, using high-resolution X-ray diffract ion of a single crystal in an electric field. The observed value of 15 (2) x 10(-12) mV(-1) is between the two values of 10.4 and 25.8 x 10(- 12) mV(-1) found in the literature. The value of d(33) is shown to be constant over the temperature range 100-220 K and no anomaly was obser ved at the conductor-insulator transition at 150 K. The results obtain ed are believed to be sample-independent, since the same value was obt ained for two different crystals, measured at different sources.