The Inverse Piezoelectric Properties of Rochelle Salt at Audiofrequencies

Abstract

Measurements of the inverse piezoelectric dilatation were made as a function of the temperature and of the frequency and intensity of the applied electric field. It was found to be proportional to the intensity of the electric field from 5 to 47 peak volts/cm for temperatures above the upper Curie point (23.8\ifmmode^\circ\else\textdegree\fi{}C) and from 5 to 40 peak volts/cm for temperatures below the Curie point; also it was found to be practically independent of the frequency from 100 to 4000 cycles/sec. and for temperatures from 13.3\ifmmode^\circ\else\textdegree\fi{}C to 35.4\ifmmode^\circ\else\textdegree\fi{}C. For temperatures below the Curie point the inverse piezoelectric dilatation increased as the frequency was decreased from 100 cycles/sec. This increase was explained in terms of Schulwas-Sorokin and Posnov's theory of relaxation time. For temperatures above the Curie point the inverse piezoelectric dilatation decreased as the frequency was decreased from 100 cycles/sec. Mueller's theory explained the experimental results for frequencies from 100 to 4000 cycles/sec. and temperatures above the upper Curie point. This theory was approximately in agreement with experiment for temperatures from 13.3\ifmmode^\circ\else\textdegree\fi{}C to the Curie point and for frequencies from 100 to 4000 cycles/sec. Below 100 cycles/sec. the theory is not in good agreement with the experimental results.