Long-time relaxation from relaxor to normal ferroelectric states in Pb0.91La0.06(Zr0.65Ti0.35)O-3

Pb0.91La0.06(Zr0.65Ti0.35)O-3 (PLZT 6/65/35) is a relaxer ferroelectric near and above the temperature of the dielectric maximum (similar to 180 degrees C). The relaxer state can persist to room temperature upon fast cooling, However, this relaxer state gradually changes to a normal ferroelectric over a long time period at 25 degrees C, characterized by an elimination of relaxer-like dielectric dispersion and a significant rhombohedral broadening and subsequent splitting of the (220) X-ray diffraction peak. A transmission electron microscopy (TEM) bright-field image of a long-time relaxed sample revealed normal micrometer-sized ferroelectric domain contrast with relaxer-like ''tweed'' structure on the submicrometer scale. The gradually structural evolution is discussed in terms of development of correlations between relaxer polar clusters.