Accession Number : AD0276937

Title :   TEMPERATURE DEPENDENT SPECTRUM OF AN ANTIFERRO-ELECTRIC LINEAR CHAIN MODEL

Corporate Author : RAYTHEON CO WALTHAM MASS

Personal Author(s) : SILVERMAN,B.D.

Report Date : APR 1962

Pagination or Media Count : 1

Abstract : Some general properties of the lattice vibrational spectra of antiferroelectric perovskite materials are proposed and illustrated with the use of a simple lattice model. It is shown that the existence of a low lying optical mode which is required to explain the dielectric properties in the cubic phase, suggests that an entire transverse optical branch should be low and temperature dependent. Each frequency of this branch can be characterized by an instability temperature. The mode with the highest instability temperature is the first to become unstable as the temperature is lowered. The calculated difference due to electrostatic interactions between the transition temperature and Curie temperature is shown to be of the same order as the observed difference for these materials. (Author)

Descriptors :   *CRYSTAL LATTICES, *FERROELECTRIC CRYSTALS, *FERROELECTRIC MATERIALS, ANTIFERROELECTRICITY, DIELECTRIC PROPERTIES, DIELECTRICS, FREQUENCY, LEAD COMPOUNDS, MATHEMATICAL ANALYSIS, PHASE STUDIES, TEMPERATURE, THEORY, TRANSITION TEMPERATURE, VOLTAGE REGULATORS, ZIRCONATES

Distribution Statement : APPROVED FOR PUBLIC RELEASE