Phenomenological and structural studies of the morphotropic phase boundary in lead zinc niobate (PZN)-lead titanate (PT)

Unknown dielectric stiffness coefficients in the elastic Gibbs free energy for Pb(Zn/sub 1/3/Nb/sub 2/3/)O/sub 3/-PbTiO/sub 3/ (PZN-PT) binary solid solution with monoclinic phase were estimated by fitting the calculated phase diagram with the available experimental one. The connecting coefficients of polarization of tetragonal and rhombohedral in a spontaneous polarization were determined by fitting the temperature change of lattice parameters in 0.91PZN-0.09PT to the calculated one. The calculated PZN-PT phase diagram using the newly estimated dielectric stiffness coefficients was in good agreement with the experimental one. The dielectric constants could be calculated at the composition near the MPB in PZN-PT.