THE ANALYSIS OF THE ATOMIC PAIR DISTRIBUTION FUNCTION OF PMN-BASED NANOPOWDERS BY X-RAY DIFFRACTION

Abstract

The three-dimensional atomic-scale structure around Mg , Nb , Ti and Zr atoms in a series ferroelectric material such as PMN, PZT, PMN-PZT and PMN-PT has been studied using X-ray diffraction ( MoK α), Rietveld refinement and the atomic pair distribution function (PDF) technique. The structure and particle size of the powders was determined by X-ray diffraction and TEM observation. The studies show that the materials are disordered at nanometer length distances. The three-dimensional atomic ordering in PMN-based nanopowders may well be described by a cubic structure of the perovskite type, similar to that occurring in the bulk crystals. At the end, the analyzed data show that the sizes of ZrO 6 octahedral are larger than TiO 6 octahedral.