Polarization effect in langasite crystals

Abstract

The variation of the resonance frequency of piezoelectric resonators subjected to a constant electric field is demonstrated with longitudinal vibrations in La3Ga5SiO14 (langasite) crystal rods at temperatures between −60 and +80°C. For the rods whose longtudinal axis makes angle α with the crystal axis \([10\bar 10]\) in the plane of the axes \([10\bar 10]\) and [0001], the change in the frequency is proportional to the field strength and depends on α. For a field of ±1.5 × 106 V/m and α = 15°, the relative change in the frequency is ±120 × 10−6. It is shown that La3Ga5SiO14 crystals offer a set of physical parameters that makes them promising for electrically controlled acoustoelectronic devices and for devices based on nonlinear interaction between acoustic waves.