Structural and Phase Transitions in the High Composition Domain of the System (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3

• Published in: Ferroelectrics 2010, Vol.400 (1), p.362-371
• Main Authors: Wang, H., Laval, J.-P., Ehrenberg, H., Fuess, H., Arrii-Clacens, S., Luo, H., Elouadi, B.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Ferroelectricity and antiferroelectricity; Phase transitions and curie point; Physics; Solid-solid transitions; Specific phase transitions
• ISSN: 0015-0193; 1563-5112
• DOI: 10.1080/00150193.2010.505857

Raman scattering, dielectric studies, powder and single crystal X-ray diffraction on 0.6Pb(Mg 1 / 3 Nb 2/3 )O 3 -0.4PbTiO 3 (PMN-40PT) and 0.55Pb(Mg 1 / 3 Nb 2 / 3 )O 3 -0.45PbTiO 3 (PMN-45PT) were carried out over a wide temperature range. Dielectric plots of PMN-45PT revealed two phase transitions with a sharp maximum at T C (paraelectric-ferroelectric transition at 485 K, from cubic to tetragonal with respective space groups Pm-3m and P4mm similar to PMN-40PT) and a second broad Raman shift at around 225 K. The Raman investigations confirmed the existence of phase transitions in PMN-45PT crystals, and the lowest frequency behaves like a soft mode. The appearance of diffuse scattering at room temperature in PMN-45PT suggests a phase distinct from PMN-40PT below T C . The identification of the symmetry in this temperature region will be further demonstrated.