Structural phase transition study of the morphotropic phase boundary compositions ofNa0.5Bi0.5TiO3–PbTiO3

Abstract

Neutron, synchrotron x-ray powder diffraction and dielectric studies havebeen performed for morphotropic phase boundary (MPB) compositions of the(1−x)Na1/2Bi1/2TiO3–xPbTiO3 system. At room temperature, the MPB compositions(0.10<x≤0.15) consist of a mixture of rhombohedral (space groupR3c) and tetragonal(space group P4mm) structures with the fraction of tetragonal phase increasing with increasingPbTiO3 content. On heating, while the rhombohedral phase just outside the MPB region, i.e. x = 0.10, transforms directly to a cubic phase, the rhombohedral phase of the MPB compositionstransforms gradually to a tetragonal phase, until interrupted by a rhombohedral–cubicphase transition. The correspondence of the dielectric anomalies with the structuraltransitions of the different compositions has been examined and compared with earlierreports.