Electromechanical Behavior of Single-Crystal Strontium Titanate

Abstract

A study of electrostriction in strontium titanate provides evidence that SrTi${\mathrm{O}}_3$ is not perfectly cubic. It exhibits a small but noticeable piezoelectric effect whose temperature and field dependence is $\frac{E}{(T-T_a)}$, whereas the electrostrictive effect was found to vary as $\frac{E^2}{{(T-T_c)}^2}$. $T_a$ and $T_c$ are the temperature of the phase transition (102.5°K) and the Curie temperature (41°K), respectively. The results of an extensive study of the compliance constant $s_{11}$ above and below the phase transition are reported and are combined with previously reported data to yield a complete set of elastic coefficients $c_{\mathrm{ik}}\mathrm{}(T,E)\mathrm{}$ or $s_{\mathrm{ik}}\mathrm{}(T,E)\mathrm{}$ as a function of temperature and externally applied electric field $E$. An accurate determination of the transition temperature as a function of electric field provides the basis for a possible check on a recent explanation of the phase transition by Cowley.