Analysis of the ferroelastic domains and phase transition in the K2SO4 crystal

The domain structures of the beta-K2SO4 crystal were analyzed by group theory. We obtained the permissible kinds of domain association and domain walls from the results of the group theory. It is suggested from the analysis that the (110) and (130) planes are W-mb walls. The value of the spontaneous strain of K2SO4 was epsilon = 6.32 x 10(-3) at room temperature and also its temperature dependence was observed.