DOMAIN BOUNDARY AND DOMAIN SWITCHING IN A CERAMIC RARE-EARTH ORTHONIOBATE LANBO4

By using TEM and X-ray diffraction, the domain structure in ceramic La NbO4 has been studied, It has been found that the domains have two dif ferent orientations, separated by a boundary with irrational Miller in dexes between (20(4) over bar)(I)/(402)(II) and (20(6) over bar)(I)/(6 02)(II) lattice planes, which is in good agreement with the boundary i ndexes calculated from elasticity theory and spontaneous strain tensor , The orientation relationship between the domains has been determined as a rotation of 95.6 degrees about the [010] axis, A model for domai n boundary configuration, a diffuse boundary with a transition zone, h as been proposed according to TEM diffraction patterns and HRTEM image s Based on this domain boundary model, a domain switching mechanism is suggested, and the corresponding driving force for domain switching i s considered.