INVESTIGATION OF FERROELASTIC DOMAIN BOUNDARY STRUCTURES OF MP(5)O(14) (M-LA-TB) AND LANBO4 BY MEANS OF SCANNING TUNNELING MICROSCOPE, ATOMIC-FORCE MICROSCOPE, X-RAY AND NEUTRON-DIFFRACTION ANALYSES

The ferroelasticity of MP(5)O(14) (M: La-Tb) which has the commensurat e W domain boundary and LaNbO4 which is believed to have the incommens urate W' domain boundary has been studied by scanning tunneling micros cope (STM), tapping-mode atomic force microscope (AFM) with a heat-sup plying apparatus, time of flight (TOF) neutron diffraction and X-ray d iffraction analyses. The tapping-mode AFM image of a GdP5O14 ferroelas tic boundary wall shows a zigzag surface structure in which hollows, w ith a width of 500-600 nm and a depth of 1 or 2 nm, are aligned along the domain boundary. Our neutron and X-ray structural analyses of LaNb O4 confirm that there is no incommensurate W' domain wall within exper imental error.