Nonlinear response to probe vitrification


Project Lunkenheimer/Loidl (Augsburg)

Investigation of nonlinear effects in glassy matter using dielectric methods


In this project, dielectric methods will be used for the investigation of nonlinear effects by performing dielectric spectroscopy in dependence of the electric field and by determining the higher harmonic terms of the dielectric susceptibility. These methods shall be applied to dipolar and ionically conducting structural glass formers and also on plastic crystals. One of the main tasks is to address the non-linear behavior of excess wing and β-relaxation, aiming at clarifying their origins by comparison with the structural α-process. Another important goal is the search for signs of a static freezing transition by exploring the temperature dependence of the non-linear susceptibility. In addition, the non-linear ionic charge transport in glass formers shall be investigated and related to theoretical predictions. The non-linearity of glassy matter will also be explored in additional experiments, where disordered matter is driven into the non-linear regime either by subjecting them to strong temperature jumps or ultrahigh pressures.

P9 Lunkenheimer/Loidl, Universität Augsburg

Investigation of nonlinear effects in glassy matter using dielectric methods

Within this project, the nonlinear properties of glassy matter will be studied using dielectric
methods. This will be primarily done by measuring the low- and high-field dielectric permittivity
and the higher harmonic components of the susceptibility. Aside of determining the nonlinear
properties of the structural relaxation, we also intend to uncover the rarely investigated behavior
of the excess wing and of the relaxation at very high electric fields. Our measurements
will provide valuable information on heterogeneity and cooperative length scales of glassy dynamics
in different classes of glass formers. Moreover, our measurements will help clarifying
the classification and origin of secondary relaxation processes in supercooled liquids.