Phase stabilities of morphotropic phases in Pb(Zn1/3Nb2/3)O3-PbTiO3 single crystals

Based on the optic and dielectric data acquired under different mechanical and electric conditions and temperature, we show that an orthorhombic phase exists near the morphotropic phase boundary (MPB) (on both the rhombohedral and tetragonal sides of MPB). Because of the proximity of the free energy of this phase to the two other morphotropic phases, i.e., the rhombohedral and tetragonal phases, the experimentally observed phases and phase diagrams near MPB depend crucially on the mechanical and electric conditions as well as the sample history. (C) 2002 American Institute of Physics.