Phase relations in the system of (Na1/2Bi1/2)TiO3–PbTiO3. I. Structure

• Published in: Journal of applied physics Vol. 79; no. 1; pp. 383 - 387
• Main Authors: Park, Seung-Eek, Hong, Kug Sun
• Format: Journal Article
• Language: English
• Published: 01.01.1996
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.362702

The region of the (Na1/2Bi1/2)1−xPbxTiO3 phase diagram from 0≤x≤0.2 was established through analysis of structure and thermal anomalies associated with changes in temperature and composition. The rhombohedral-tetragonal morphotropic phase boundary (MPB) was investigated considering the dependence of the rhombohedral lattice distortion of (Na1/2Bi1/2)TiO3 (NBT) on chemical stoichiometry and fabrication processes. It was found that the MPB would lie in the composition range 0.13<x<0.15 when the lattice constant and lattice distortion of (Na1/2Bi1/2)TiO3 are 3.886 Å and 89.6°, respectively. The phase transition sequence of (Na1/2Bi1/2)1−xPbxTiO3 was rhombohedral↔tetragonal↔cubic as that of pure NBT when x was less than MPB composition. However, the intermediate tetragonal phase has either low tetragonal distortion for compositions with x<xrc (composition where rhombohedral↔cubic transition exists) or high tetragonal distortion for compositions with x≳xrc. The changes in structure and phase transition behavior of this solid solution system with temperature and composition are discussed.