Structural study of Pb(Fe2/3W1/3)O3–PbTiO3 system

December 2002

Materials Letters 57 (2002) 609 – 614 www.elsevier.com/locate/matlet

Structural study of Pb(Fe2/3W1/3)O3 –PbTiO3 system Liliana Mitoseriu a,b,*, Paula M. Vilarinho a, Massimo Viviani c, Joa˜o L. Baptista a a

Department of Ceramics and Glass Engineering/UIMC, University of Aveiro, 3810, Portugal b Department of Electricity, Faculty of Physics, University Al. I. Cuza Iasi, 6600, Romania c ICFAM-CNR, Via de Marini 6, Genoa 16149, Italy Received 28 February 2002; accepted 14 April 2002

Abstract The crystalline structure of the solid solution (1
x)Pb(Fe2/3W1/3)O3 – xPbTiO3 (PFW – PT) with x=0, 0.2, 0.25, 0.3, 0.35, 0.4 and 1 was analysed using X-ray diffraction (XRD) with comparative cell-refinement methods, in order to detect the change in symmetry with composition. Pure PFW shows pseudo-cubic symmetry for temperatures in the range 85 – 423 K. For the temperatures T=85 K and T=300 K, the solid solutions have cubic or tetragonal structures. The cell constants are functions of PbTiO3 amount. A temperature-dependent Morphotropic Phase Boundary (MPB) separating the pseudo-cubic (relaxor) and tetragonal (ferroelectric) phases might be present. The ranges of compositions for this boundary are: x