Effect of uniaxial stress on the unstable A₁ (TO) phonon in ferroelectric gadolinium molybdate

Authors

B.N. Ganguly, University of Nebraska - Lincoln
Frank G. Ullman, University of Nebraska - Lincoln
Roger D. Kirby, University of Nebraska-LincolnFollow
J.R. Hardy, University of Nebraska - LincolnFollow

Date of this Version

November 1975

Comments

Published by American Physical Society. Phys. Rev. B 12, 3783 (1975). http://prb.aps.org. Copyright © 1975 American Physical Society. Permission to use.

Abstract

The effect of uniaxial stress along [100] on the unstable A₁ (TO) phonon, 47 cm^-1 at room temperature, in ferroelectric (<159°C) gadolinium molybdate has been studied by Raman scattering at 138, 141, 146, and 155°C. An increase in peak frequency and narrowing of the line shape is observed with increasing stress. The data are analyzed by fitting to a Lorentzian line shape. The force-constant parameter is insensitive to both stress and temperature, whereas the damping constant decreases nonlinearly with stress, approaching an asymptotic value at high stress.