Accession Number : AD0727837

Title :   Surface Properties of Semiconductors and the Dynamics of Ionic Crystals,

Corporate Author : FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : Murzin,V. N.

Report Date : 26 JUN 1971

Pagination or Media Count : 106

Abstract : Absorption and reflectance spectra of crystalline SrT:O3, BaTiO3, and Cat:O3 in the IR spectral range were obtained on a long wavelength IR spectrometer. An analysis of the vibrational modes of compounds having the perovskite structure is given and its application to the experimental spectra is shown by using Cochran's dynamic theory of crystal lattices. At a temperature close to a phase transition, BaT:03 showed a marked lowering of its spectral frequencies and an increase of oscillator strength of the lowest vibrational frequency. These observations were predicted by Ginzburg, Anderson, and Cochran and this article gives the first reported data which are in agreement with this prediction. (Author)

Descriptors :   (*FERROELECTRIC CRYSTALS, INFRARED SPECTROSCOPY), BARIUM COMPOUNDS, CALCIUM COMPOUNDS, STRONTIUM COMPOUNDS, TITANATES, DIELECTRIC PROPERTIES, PHONONS, USSR

Subject Categories : Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE