Regensburg 2013 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 11: Poster: Glasses and Glass Transition (joint session DY/CPP)

CPP 11.10: Poster

Montag, 11. März 2013, 17:30–19:30, Poster C

Non-universal dielectric and elastic properties of glasses at very low temperatures — •Annina Luck, Marius Hempel, Andreas Fleischmann, and Christian Enss — Kirchhoff-Institut für Physik, Universität Heidelberg

Based on many experimental observations the low temperature properties of glasses, governed by atomic tunneling systems, have long been viewed as being universal. In the last years, however, measurements of dielectric two-pulse polarization echoes have revealed that nuclear electric quadrupole moments involved in atomic tunneling systems can cause large material-dependent effects in magnetic fields.

To study the possible influence of nuclear electric quadrupoles in two level systems on the low frequency dielectric and elastic properties of glasses down to a temperature of 10 mK, we measured vitreous silica and the multicomponent glass N-KZFS11, which contains 25 mass percent of tantalum oxide. As ¹⁸¹Ta carries a very large nuclear electric quadrupole moment, N-KZFS11 seems to be an ideal candidate to determine the influence of nuclear electric quadrupole moments on the physical properties of glasses at low temperatures.

Our measurements not only show a non-universal dieletric and elastic behaviour for these two glasses, but the results also differ significantly from various predictions of the standard tunneling model. We discuss these new findings and possible implications in terms of the tunneling model.