Ferroelectric‐Paraelectric Phase Transition in Lead Titanate Containing Lattice Defects

Abstract

A series of lead titanates containing lattice defects was prepared and characterized in terms of inhomogeneously distributed vacancies, □ Pb and □ O• . The tetragonal lattice strain and the Curie temperature varied as functions of the Pb or O deficiency in the crystals. The tetragonal strain for these crystals decreased slowly with increasing temperature as the Curie temperature was approached. The phase transition, which extends over a temperature interval, is interpreted according to a model in which microregions in the crystal differ in composition and therefore have different Curie temperatures.