Temperature characteristics of langanite bulk wave vibrations

Abstract

Langanite (NGL) is the promising material for FC applications. In present work we measured NGL piezoelectric constants at temperature range -196/spl deg/C-+120/spl deg/C. This results and previous data on temperature dependencies (TD) other constants enabled to make the complete theoretical analysis of thickness vibration parameters of NGL single and double rotation cuts in wide temperature range. Thermally compensated xybl//spl alpha///spl beta/ cuts were theoretically found for several modes. For slow shear mode first and second order temperature coefficients (TC) could be zero simultaneously. From our calculations resonator frequency shift at temperature range could be 2-4 times better than SGL one. High quality NGL single crystals were grown by Czochralski method NGL plane, plano-convex and double-convex plates were prepared and tested at temperature range 15/spl deg/C-120/spl deg/C on fundamental and 3, 5, 7 overtone frequencies. It experimentally suggested zero cuts existence. From above data and possibility to grow high quality single crystals NGL seems to be more promising compare with SGL.