Electroacoustic Coefficients for Strontium Titanate in the Vicinity of Structural Phase Transition

A.Korobov, Yu.A.Brazhkin, N.I.Odina (Department of Acoustics, Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow, Russia)

e-mail: akor@acs465a.phys.msu.ru

The results of experimental investigation of electroacoustic  coefficients for strontium titanate single crystal in the vicinity of  structural phase transition are presented. The measurements of  relative change of 30-MHz-longitudinal wave velocity as a  function of external electric field are carried out. Electric field is  applied along or perpendicularly to the wave propagation direction.  The linear additions to square-law dependence of ultrasound  velocity as a function of electric field are observed by  approaching to phase transition temperature in both cases. The  linear addition is more significant when electric field is  perpendicular to wave propagation direction. The linear addition  appearance can be related to piezoelectric contribution which  can be explained by a deviation of lattice symmetry from cubic  that is stimulated by defects.


Section : 2