Effect of External Stress on the Domain Structure of WO₃

Abstract

WO 3 is monoclinic at room temperature and has a domain structure with walls of (110) and (100) twin planes. The (110) wall is displaced sideways by a pressure externally applied along the b axis, resulting in the change of the axis b to the shorter axis a . The (100) domains change to a single domain by stress X z . The single domain crystal obtained in this way is used to determine the optic elasticity axes of WO 3 . Two peculiar types of domain structure appear by a pressure along the c axis, which can be understood as resulting from the change of the axis c to the axis a by the stress. This sensitivity of domain structure to the stress seems to be due to the monoclinic and pseudosymmetric structure of this crystal.