Ferroelastic and 90∘ ferroelectric domains in Bi2WO6 single crystals

Abstract

High-quality single crystals of [Formula: see text] are grown using a flux method. With different flux growth recipes, we aim to control the crystallization temperature to be lower and higher than the ferroelectric transition temperature, resulting in mono-domain and multi-domain [Formula: see text] crystals, respectively. Abundant ferroelastic orthorhombic twin domains are observed in the multi-domain crystals under an optical microscope. PFM studies unveil the 90[Formula: see text] polarization change across those ferroelastic domain walls, as well as the absence of 180[Formula: see text] ferroelectric domains in the as-grown multi-domain crystals, indicating a high energy cost of 180[Formula: see text] ferroelectric domains. Moreover, a 45[Formula: see text] tilt of the 90[Formula: see text] ferroelectric domain walls is discovered, and this tilt creates a new type of charged 90[Formula: see text] ferroelectric walls, which have not been observed in other bulk ferroelectrics.