Accession Number : AD0846255

Title :   Anharmonic Mode-Mixing in Ionic Ferroelectrics,

Corporate Author : CORNING GLASS WORKS RALEIGH NC ELECTRONICS DIV

Personal Author(s) : Englman, Robert ; Yatom, Haim

Report Date : 01 AUG 1966

Pagination or Media Count : 14

Abstract : The effects of various anharmonic interactions between the soft mode and other modes in an ionic ferroelectric have been examined, with a view of predicting sudden temperature variations in the frequencies of the latter. The normal coordinates and frequencies of the deformation modes (even modes connected with electrostriction) change at the transition points in a way depending on whether the anharmonic coupling is of the third or of the fourth order. The longitudinal optical mode when coupled to the transverse mode changes discontinuously in the way observed by Perry and Hall, provided an isotropic coupling is assumed; however, the continous variation of the longitudinal frequency with temperature is not given by the mechanism. (Author)

Descriptors :   (*FERROELECTRIC CRYSTALS, VIBRATION), INTERACTIONS, TEMPERATURE, FREQUENCY, ELECTROSTRICTION, ISRAEL.

Subject Categories : Crystallography
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE