ACOUSTIC WAVE DEVICE COMPRISING LITHIUM NIOBATE MATERIAL AND / OR LITHIUM TANTALATE OF OPTIMIZED LOW COEFFICIENT TCF COMPOSITION AND PROCESS FOR PRODUCTION OF SAID MATERIAL

摘要

The subject of the invention is an acoustic wave device comprising a piezoelectric material of lithium niobate and / or lithium tantalate and control electrodes, characterized in that said piezoelectric material corresponds to one of the following compositions: - Li Nb O with x a molar fraction such that: 0.97 = 1-x = 1.02 and delta a weak molar fraction in front of 1; - Li Ta O with a molar fraction such that: 0.97 = 1-y = 1.02 and delta a weak molar fraction in front of 1; - Li Nb Ta O with z, p and q molar fractions, such that: 0 = 1 + p = 1.03, 0 = 1 + q = 1.03 and 0.97 = 1 - z = 1.02 and delta a weak molar fraction in front of 1; said piezoelectric material having an absolute value of TCF of less than about 20 ppm / ° C.