On the conceration dependence of the phase transition temperature in solid solutons of a quantum paraelectric and a feroelectric component near the quantum limit

Abstract

The lattice dynamics of solid solutions with a quantum paraelectric and a ferroelectric component is considered. Using the self-consistent phonon approximation and the coherent potential approximation the phonon spectrum of the disordered lattice is obtained and the dependence of the phase transition temperature T_c on the concentration × of the ferroelectric component is calculated near the quantum limit. The theoretical result T_c ∼(x-x_c)^1/2 is in excellent C agreement with the experimental findings.