DISORDERED OXYGEN OCTAHEDRAL ROTATIONS AND GLASSLIKE POLARIZATION CHARACTERISTICS IN RHOMBOHEDRAL LEAD-ZIRCONATE-TITANATE

Disordered oxygen octahedral rotations have been observed in the low-t emperature rhombohedral ferroelectric state in the Pb(Zr1-xTix)O-3 cry stalline solution. The development of disordered oxygen octahedral rot ations within the ferroelectric state was found to result in the inter ruption of long-range polar order and the development of fluctuation e ffects. Dielectric relaxation was observed below similar to 160 degree s C for Pb(Zr0.65Ti0.35)O-3. In addition, double-looplike characterist ics were observed in the polarization electric-field (P-E) response in the same temperature range. The results clearly reveal the nature of the coupling between the polarization and oxygen octahedral rotations in a perovskite ferroelectric structure. It was also shown that a smal l amount of La doping can enhance the degree of ordering of the octahe dral tilted state. The enhancement of the ordering was verified by an intensity increase of the 1/2[111] superlattice reflections in the sel ected area electron-diffraction pattern. (C) 1996 American Institute o f Physics.