PHASE-DIAGRAM PECULIARITIES OF PZT WITH SMALL TITANIUM CONTENTS

Indirect interaction of random site and orientation electric dipoles t hrough antiferroelectric and structural phase transition soft mode is calculated. Distribution function of random electric field induced by sum of this interaction and that through ferroelectric soft mode is ob tained,in the statistical theory framework. This distribution function made it possible to calculate transition temperature, critical concen tration and order parameter of ferroelectric phase induced by the dipo les. The developed theory applied to PbZrO3 with small concentration ( less than or equal to 5%) of Ti ions. Calculated concentrational depen dence of ferroelectric and antiferroelectric phase transition temperat ures fitted very good the observed transition temperatures.