Thermal expansion and polarization of (1-x)PNN-xPT solid solutions

The paper presents the results of detailed studies of the thermal expansion of (1-x)PbNi_1/3Nb_2/3O₃-xPbTiO₃ solid solutions with x = 0-0.8. The anomalous and lattice contributions to deformation and the thermal expansion coefficient are analyzed and the mean square polarization P_d is determined. The results obtained are discussed within the framework of the thermodynamic theory and the Landau 2-4-6 coefficients for solid solutions are estimated.