Microtexture Studies of PST and PZT Ceramics and PZT Thin Film by Electron Backscatter Diffraction Patterns

C W Tai,K Z Baba-Kishi

doi:10.1080/0730330021000000191

Abstract

Crystallographic orientations of twelve different lead scandium tantalate (PST) ceramics, two lead zirconate titanate ceramics (PZT) and one PZT thin film were investigated by the technique of electron backscatter diffraction (EBSD) in the scanning electron microscope. The PST ceramics were processed under different conditions of temperature and annealing. Crystal orientations in the bulk ceramics were examined and the results were plotted in microtexture pole‐ and inverse pole‐figures. Local texture and misorientation between adjacent grains in certain selected regions of the ceramics were also examined. To compare the results of the PST with another lead‐based ferroelectric material, an unpoled and a poled PZT ceramics were studied for their texture. The electrical and electromechanical properties of the PZT ceramics were also measured in an attempt to correlate texture with properties. Extensive studies revealed insignificant texture in the ceramics, indicating no relationship between ferroelectricity and texture. Preferred orientations were observed in a PZT thin film grown by pulsed‐laser deposition (PLD) method. Though improved anisotropy in PZT thin films can be attributed to texture, there is no indication of the dependence of piezoelectricity on texture.

Highlights

Most solid-state materials are polycrystalline consisting of grains separated by grain boundaries
The crystallographic texture results, that are similar to the studies on the coefficient of electrostriction Q11 (Birks et al, 1999) and the general profile of temperature dependence refractive index n(T ) (Korshunov et al, 1989), are not significantly related to the degree of structural order
The variations in dielectric constants of PST materials are not influenced by the existence of random texture

Summary

INTRODUCTION

Most solid-state materials are polycrystalline consisting of grains separated by grain boundaries. 32 grains and FIGURE 3 (a) ND, (b) RD and (c) TD microtexture inverse pole-figures of the large grains in the PST(ann-950) sample. In the extensive study of the local texture in PST ceramics, crystallites were randomly oriented and showed no significant relationship. In the study of PZT ceramics, the overall and local textures of two samples, one of which was poled and the other unpoled, were examined. The clustering at the center originates from two groups of orientations, FIGURE 7 Microtexture pole-figures of the PZT ceramic thin film. The general expression of the thin film texture can be re-written as {100}h0 0 1i

Findings

DISCUSSION

CONCLUSION