Piezoelectric and Elastic Properties of Lithium Niobate Single Crystals

Piezoelectric and elastic constants of lithium niobate single crystal were measured in the temperature range between 20°C and 200°C. These constants were obtained by measuring the resonant and antiresonant frequencies of the length-extensional mode of bars with various orientations. The measured constants are all of the piezoelectric strain constants and the dielectric constants and a part of the elastic compliances, namely, s E 11, 2s E 13+s E 44, s E 14 and s E 33. Values at 20°C and their temperature dependence are as follows. The constants d and s are expressed in units of 10-8 statcoulomb/dyn and 10-12 cm2/dyn, respectively: d 15=222[1+(T(^°C)-20)2.8×10-4]; d 22=62.3[1+(T-20)×2.4×10-4]; d 31=-2.59[1+(T-20)11×10-4]; d 33=48.7[1+(T-20)2.9×10-4]; s 11 E =0.564×[1+(T-20)1.5×10-4]; 2s 13 E +s 44 E =1.39[1+(T-20)2.0×10-4]; s 14 E = -0.084; s 33 E =0.494[1+(T-20)1.5×10-4]; ε 11 T =84.6; ε 33 T =28.6; k 31=0.02; k 22=0.32; k 33=0.47. The electromechanical coupling factor k'31 of z y w-45°-cut bar amounts to 0.50.