Hamburg 2001 – scientific programme

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DF: Dielektrische Festkörper

DF 5: Gl
äser

DF 5.2: Fachvortrag

Tuesday, March 27, 2001, 15:10–15:30, S18/19

Aging and Memory Effects in Methanol-β-Hydroquinol Clathrate — •Maikel Rheinstädter, André Kityk, and Klaus Knorr — Universität des Saarlandes, Technische Physik, 66123 Saarbrücken

The physics of systems out of thermal equilibrium is an old but nevertheless up to date field of interest with still numerous open questions. Typical examples of out-of-equilibrium systems are glasses, i.e. structural glasses, spin glasses in the case of magnetic interactions and their electric pendants, the orientational glasses. In these materials, the existence of a slow relaxation channel leads to physical aging. In comparison with aging due to an external influence like chemical reaction or mechanical fatigue, physical aging here means a spontaneous long time evolution. This effect is seen in the corresponding response functions, i.e. the magnetic or electric susceptibility. A typical aging experiment is to stabilize a temperature below the glass transition temperature and to continuously measure χ″ or є″, respectively. When cooling is resumed and the system is heated again, our system perfectly traces the previous aging history, it shows a memory effect. We present and discuss our measurements on methanol-β-hydroquinol clathrate¹ , which belongs to the class of orientational glasses.

[1] H. Woll, M. Enderle, A. Klöpperpieper, M.C. Rheinstädter, K. Kiefer, F. Kruchten and K. Knorr, Europhys. Lett. 51 (4), 407 (2000).