THE ELASTIC CONSTANTS OF STRONTIUM TITANATE

Abstract : The elastic constants c sub 11, c sub 12, and c sub 44 of single crystal strontium titanate have been measured as a function of temperature from 300 to 112 K by determining the velocity of an ultrasonic wave. At 112 K, the strontium titanate undergoes a phase transition to a tetragonal structure which causes a marked change of the elastic properties and the appearance of a domain structure, but does not cause a discontinuity of the dielectric constant. The phase transition is free of hysteresis. The dependence of the elastic properties on a dc electric field parallel to the velocity of sound propagation was measured and found independent of the dielectric properties. The implications of this result are discussed. (Author)