Both lithium niobate and lithium tantalate are ferroelectric crystals which possess high Curie temperatures. These crystals exhibit excellent piezoelectric coupling coefficients, making them attractive for ultrasonic device applications.
(1) The composition of crystal SiO2, at different temperatures under atmospheric pressure, the structure of quartz crystal is different, temperature T < 573℃ α quartz crystal, when 573℃ < T < 870℃ β quartz crystal, melting point is 1750℃, we usually say the piezoelectric quartz crystal refers to α quartz crystal.
The quartz, a very important piezoelectric material, is raw material for making quartz crystal resonators. Its main feature is that its atoms or molecules are arranged regularly, which reflects the symmetry of the shape on a macroscopic scale.