Direct measurement of pyroelectric figures of merit of proper and improper ferroelectrics

Abstract

A direct method is described for measuring the figures of merit which characterize the performance of pyroelectric materials as infrared vidicon targets or point detectors. The results of experiments carried out as a function of temperature on a proper ferroelectric, triglycine sulfate, and an improper ferroelectric, terbium molybdate, are compared with the predictions of the appropriate thermodynamic theories. It is shown that within the family of rare-earth molybdates isomorphic to terbium molybdate there exists an optimum value for the figure of merit relevant to pyroelectric vidicon performance.