Domain Structure and Deflection of Light at Domain Walls in RbHSeO4

Domain structures of feroelectric RbHSeO 4 , which undergoes phase transitions at 102°C and 173°C, were observed and examined in the presence of either electric field or shear stresses, and the intensity of a laser beam deflected at domain walls was measured. In addition, dielectric and piezoelectric examinations were made above and below the 102°C transition. It was found that there are two types of domain structures observable at room temperature, i.e., the ferroelectric and simultaneously ferroelastic domain struc-structure with the (001) domain walls and the ferroelastic one with the (100) domain walls. The former is observable below 102°C, while the latter is observable even above 102°C. The intensity of the light beam deflected at the (001) domain walls is observed to be proportional to the square of the spontaneous polarization.