Thermal expansion studies in the lead iron niobiate — Lead titanate system

Compositions in the solid solution series {Pb(Fe0.5Nb0.5)O3}1 − x — {PbTiO3}x (x = 0 → 1) were prepared by solid state reaction. The phase transition from rhombohedral/tetragonal to cubic structure has been studied as a function of x by differential thermal analysis, high temperature x-ray diffraction and dilatometry in the temperature range 298–773K. Dielectric measurements and thermal expansion coefficients of the x = 0.2 composition indicate that the relaxor type behaviour of lead iron niobate is extended up to 453K.