1980 年 36 巻 7 号 p. 350-356
In this paper, the properties of Rayleigh wave propagation on two- or three- layered structures using LiNbO_3, LiTaO_3 and SiO_2 are studied theoretically and experimentally. The properties of the SiO_2/(ZY)LiNbO_3 structure relevant to Rayleigh wave propagation are studied, and it is shown that the piezoelectric coupling coefficient is 3. 8% with a zero temperature coefficient of the delay. It is theoretically found that the LiTaO_3 layer has the property of a wave guide and the poynting power is concentrated in the LiTaO_3 layer in the SiO_2/(ZY)LiNbO_3 structure. Furthermore, the approximate equation of temperature coefficient of the wave velocity for multi-layered structures is proposed. The coefficient of linear expansion of the substrate has been usually used for the approximate value of that of a layered structure. In this paper, the coefficient of linear expansion of the layered structure is theoretically investigated. Experimentally the insertion loss (or the piezoelectric coupling coefficient) and the temperature coefficient as a function of the SiO_2 thickness are measured for the SiO_2/(ZY)LiNbO_3 and the SiO_2/(ZY)LiTaO_3/(ZY)LiNbO_3 structures. The zero temperature coefficients can be obtained for both structures.