A SYNCHROTRON X-RAY STUDY OF FERROELECTRIC SWITCHING, DOMAIN REVERSAL AND PIEZOELECTRIC MODULI IN CSTIOASO4 UNDER AN APPLIED ELECTRIC FIELD

摘要

Single crystals of caesium titanyl arsenate (CTA, CsTiOAsO4), with space group Pna2(1) and isomorphous with potassium titanyl phosphate (KTP, KTiOPO4), have been studied using high-resolution synchrotron X-rays. During the experiments, an electric field was applied along the polar axis [001]. Single-crystal plates, between 300 and 450 mu m thick along [001], were polarized by a variable square wave of frequency 20 Hz alternately applied to each side of the plate. A field-induced splitting of the + / - peaks for reflections hkl with l not equal 0 was observed. This splitting provides information about the coercive field, polarizability and the piezoelectric strain tenser. Two of the piezoelectric coefficients of CTA could be estimated as d(31) similar or equal to 1 and d(33) similar or equal to 27 pm V-1. Whereas the coercive fields were estimated at 2300 Vmm(-1) the held necessary to reverse the domains just once in CTA was found to be either 560 or 1550 V mm(-1), depending on the polarity of the reversed domain in relation to the polarity of the nonswitched part of the crystal. [References: 20]