Europhys. Lett.
Volume 65, Number 1, January 2004
Page(s) 55 - 60
Section Condensed matter: structure, mechanical and thermal properties
Published online 01 December 2003
Europhys. Lett., 65 (1) , pp. 55-60 (2004)
DOI: 10.1209/epl/i2003-10049-7

Coexistence of two universal relaxations in the glassy freezing of a deuteron dipole glass

Y.-S. Choi and J.-J. Kim

Physics Department, Korea Advanced Institute of Science and Technology Taejon 305-701, Korea

(Received 23 July 2003; accepted in final form 23 October 2003)

A deuteron dipole glass $\chem{Rb}$ 1-x(ND 4) xD 2PO 4 (DRADP- x, x=0.47) was studied on glassy freezing by low-frequency dielectric measurements at low temperatures of slow dynamic freezing. A very broad distribution of relaxation times (relaxation frequencies) was observed to show an apparent crossover behavior from the relaxation time distributions with a long-time (low-frequency) tail to the distributions with a short-time (high-frequency) tail as temperature was lowered to below 40 $\un{K}$. We show that this apparent crossover behavior may be originated by two competing relaxations in coexistence: one characterized by an Arrhenius law and the other by an inverse Arrhenius law temperature dependence, corresponding to the two slow-relaxation modes ( C<0 and C>0) of the dynamically correlated domains (DCDs) model of Chamberlin et al.

64.70.Pf - Glass transitions.
77.22.Gm - Dielectric loss and relaxation.
78.30.Ly - Disordered solids.

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