Microstructural and electrical characterization of La-doped PZT ceramics prepared by a precursor route

The effect of a powder processing route on the microstructure and electrica l properties of 2 mol% La-doped PZT powders with tetragonal, rhombohedral a nd morphotropic compositions was investigated. Powders were prepared by usi ng mixed-oxide and precursor methods, and different sintering regimes were used to control the grain size of the ceramics. It was shown that, by using the precursor method, ceramics with a submicrometer grain size and a narro w grain size distribution could be obtained. In addition, the precursor met hod results in ceramics with higher chemical homogeneity with respect to th e Zr/Ti-distribution within the grains compared to the mixed-oxide route. I n the case of the morphotropic composition, the chemical homogeneity affect s the magnitude of the coercive field. The coercive field also increases wi th decreasing grain size, due to larger internal elastic stresses related t o grain boundaries. (C) 2001 Elsevier Science Ltd. All rights reserved.