Phase transitions and properties of perovskite ferroelectric ceramics and films for certain applications

The structure-properties relationships and phase transitions in perovskite ceramics, and films of PLZT, PLZST, PST, PSN, PMNT compounds are discussed with regard to ordering, relaxer behaviour, pronounced ferroelectric, elect romechanical and electrocaloric properties. The theoretical approach is ext ended to the time dependent Ginsburg-Landau model. The evolution of dielect ric properties in relaxors after the change of temperature and electric fie ld creating an increase of dielectric permittivity is found to follow a log arithmic law of decay. A strong electromechanical response is observed in a number of thin films of different compositions.