Berlin 2012 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 29: Posters II

DY 29.25: Poster

Donnerstag, 29. März 2012, 17:00–19:00, Poster A

Investigation of dielectric and elastic properties of glasses at very low temperatures in the low frequency regime — •Annina Luck, Marius Hempel, Andreas Reiser, Andreas Fleischmann, and Christian Enss — Kirchhoff-Institut für Physik, Universität Heidelberg

In the last years, measurements of dielectric two-pulse polarisation echoes have revealed that nuclear electric quadrupole moments involved in atomic tunneling sytems can accord for the magnetic field dependence of the echo amplitude of non-magnetic glasses.

To investigate the influence of nuclear electric quadrupoles on the low frequency dielectric and elastic properties of glasses down to a temperature of 7 mK, we measured samples of the glass N-KZFS11 which contains 25 mass percent of tantalum oxide. As ¹⁸¹Ta carries a very large nuclear electric quadrupole moment, the measured sample seems to be an ideal candidate to determine the influence of nuclear electric quadrupole moments on the physical properties of glasses at low temperatures.

The tunneling model predicts a slope ratio of 2 for the logarithmic temperature dependence of the susceptibility, caused by resonant and relaxational processes. Our results show a surprising accordance with this prediction of the tunneling model, which as of now has never been observed in other glasses.

We discuss these experimental results in the context of the tunneling model and possible extensions of it.