Elastic and piezoelectric properties of Ba2Si2TiO8

摘要

All the elastic constants, temperature coefficients of elastic constants, and thermal‐expansion coefficients in Ba2Si2TiO8 were measured. Signs of the piezoelectric constants d31 and d15 were determined to be positive. From the calculations of the orientational dependences on the electromechanical coupling factors k′31 and k′15 and the temperature coefficient of resonance frequency [Tfr]L in the length‐extensional mode, it was found that the largest values of k′31 and k′15 are 0.13 and 0.28, respectively, and the minimum value of [Tfr]L is -47 ppm/°C. Surface‐acoustic‐wave analysis for the crystal showed that the SH‐mode piezoelectric surface wave has a piezoelectric coupling constant, k2=0.0053, larger than that of quartz, and a temperature coefficient of delay Tτ=+38 ppm/°C for the Y‐propagation direction on the X‐cut surface, smaller than that of LiNbO3.