Behaviour of thermal expansion of (1-x)Pb(Ni1/3Nb2/3)O-3-xPbTiO(3) solid solutions

The features of the dependence of the bulk coefficient of thermal expansion of the (1-x)Pb(Ni_1/3Nb_2/3)O₃–xPbTiO₃ solid solution studied in the series of x = 0–0.8 in the temperature range from 100 to 750 K are reported. The obtained data and observed anomalies of thermal expansion are compared with dielectric properties, heat capacity, and the phase diagram of concentration. The anomalous and lattice constituents of deformation and of the coefficient of thermal expansion are analysed and the data on deformation are used to estimate the Burns temperature and the mean square polarization of the samples found to decrease with the decrease of the PbTiO₃ concentration.