Regensburg 2010 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 25: Glasses II (joint session of CPP, DF, DY)

DY 25.4: Vortrag

Donnerstag, 25. März 2010, 10:30–10:45, H38

Dielectric noise pattern of the Debye- and α-process in a monohydroxy alcohol — •Tobias Gamp, Andreas Reiser, and Christian Enss — Kirchhoff-Institut für Physik, Universität Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg

Based on the validity of the fluctuation dissipation theorem, dielectric polarization noise spectroscopy allows to measure the dielectric function of a sample electrically non-driven. 2-Ethyl-1-hexanol is one of the prototypical and widely studied glass-forming liquids showing a Debye-like relaxation and the α-peak, the latter associated with the structural relaxation. Since the Debye process is practically invisible in caloric measurements but prominent in conventional dielectric spectroscopy the question whether it could be caused by the presence of electric fields is debated. We show dielectric noise spectra - both voltage and current power spectral densities - and conventional dielectric spectra. Within our experimental resolution and the validity of the fluctuation dissipation theorem both sets of data are in agreement, indicating that the presence of an external field is not necessary for the occurrence of such a Debye peak.