Mark W. Dowley
Solid State Communications
Cooperative polarization fluctuations in mixed Rb1-x(NH4)xH2PO4 single crystals have been investigated with optical and dielectric measurements. Raman scattering reveals a soft mode at temperatures above those at which the glass anomalies first occur (T≳110 K). This mode continues slowing down on further cooling, but leaves behind a trail of hard modes. These evolve into a broad distribution of relaxations which have now been followed with Brillouin scattering, with audio-frequency dielectric measurements and with long-time sample-charging experiments. This freezing dynamics could be measured over approximately 17 orders of magnitude in frequency. One finds that the temperature dependence of the lowest frequency (or "cut-off" frequency) characterizing the distribution of relaxations is extremely well represented by the phenomenological Vogel-Fulcher law. It cannot be accuunted for as well by other laws, such as those proposed for spin glasses. © 1986 Springer-Verlag.
Mark W. Dowley
Solid State Communications
Michiel Sprik
Journal of Physics Condensed Matter
Kigook Song, Robert D. Miller, et al.
Macromolecules
I.K. Pour, D.J. Krajnovich, et al.
SPIE Optical Materials for High Average Power Lasers 1992