Evaluation of Material Constants and Temperature Properties in Lanthanum Calcium Oxoborate LaCa 4 O(BO 3 ) 3 Single Crystals

Lanthanum calcium oxoborate LaCa 4 O(BO 3 ) 3 (LaCOB) single crystals were successfully grown by the Czochralski technique. It was found that LaCOB crystals belong to the monoclinic system (point group m ) and the total number of independent material constants that should be determined is 27. Twenty-four of the 27 material constants at room temperature were determined by the resonance-antiresonance method. The normalized first-order temperature coefficients of some constants e.g. , ε 11 T , ε 22 T , ε 33 T and ε 13 T determined at 10 kHz were 56.30, -273.6, 135.8 and -258.4 and d 11 and d 12 were -408.3 and 83.60 ppm/°C, respectively. Additionally, the thermal expansion coefficients e.g. , α 11 , α 22 and α 33 determined on a single crystal cut along the X , Y and Z rectangular directions by the thermodilatometry measurement were 7.36×10 -6 , 8.17×10 -6 and 11.4×10 -6 /°C, respectively. As a result of the evaluation, most of the material constants and temperature properties necessary for investigating the properties of piezoelectric devices typified by SAW were obtained.