Thermodynamic Phenomenology for Perovskite Structure Ferroelectric Solid Solutions with Morphotropic Phase Boundaries

摘要

The report covers the period June 1 2001 to April 30% 2004 on the Office of Naval Research Grant N00014 01-1-870 on the topic 'Thermodynamic Phenomenology for Perovskite Structure Ferroelectric Solid Solutions with Morphotropic Phase Boundaries'. Topics for study which will be reported include: Lower temperature (down to 12K) studies of the dielectric properties of single crystal lead zinc niobate: lead titanate. Studies of a new two order parameter model for lead zirconate titanate which leads naturally to the occurrence of the lower temperature monoclinic phase interleaving the tetragonal: rhombohedral classical MPB. Application of the flexoelectric measurement technique developed on the ONR US; Japan Global studies program to explore strain gradient drive of ferroelastic domain walls and the development of a new thermodynamic function for BaTiO3 to better describe the high temperature phase transitions evidenced under large epitaxial strains in thin BaTiO3 films on non matching substrates.