A Synchrotron X‐ray Study of Ferroelectric Switching, Domain Reversal and Piezoelectric Moduli in CsTiOAsO4, Under an Applied Electric Field

Single crystals of caesium titanyl arsenate (CTA, CsTiOAsO 4 ), with space group Pna2 1 and isomorphous with potassium titanyl phosphate (KTP, KTiOPO 4 ), 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 μm 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 1 ¬= 0 was observed. This splitting provides information about the coercive field, polarizability and the piezoelectric strain tensor. Two of the piezoelectric coefficients of CTA could be estimated as d 31 ≃ 1 and d 33 ≃ 27 pm V -1 . Whereas the coercive fields were estimated at 2300 V mrn -1 , the field necessary to reverse the domains just once in CTA was found to be either 560 or 1550 V mrn -1 , depending on the polarity of the reversed domain in relation to the polarity of the nonswitched part of the crystal.