Mechanical Relaxation and Nonlinearity in Strontium Titanate Single Crystals

Abstract

Abstract The temperature dependence of the resonance frequency of longitudinally vibrating [;100] bars of SrTiO 3 single crystals exhibits two maxima at T a = 103 °K and T b = 30 °K. Between these temperatures exact measurements are only possible if the exciting voltage is sufficiently low. At higher amplitudes nonlinear response can be observed. The maximum at T a is shifted to higher temperatures by applying a uniaxial stress P (d T a /d P = 18 × 10 −3 deg/at) and hydrostatic pressure p (d T a /d p = 1.5 × 10 −3 deg/at). After changing the mechanical and electric bias, mechanical relaxation occurs in the temperature range between 30 and 80 °K.