Measurements of the Electrical Properties of Ice Ih Single Crystals by Admittance and Thermally Stimulated Depolarization Techniques

Abstract

Ice Ih single crystals were investigated by complex admittance and thermally stimulated depolarization (TSD) techniques, in the relaxation-time ranges 10–5–10 s and 10–104 s respectively. The relaxation spectrum was resolved and three components of it were studied. Second-order kinetics had to be assumed for two of the TSD spectra to obtain Arrhenius-type relaxation times. The “Debye spectrum” had an activation energy for the relaxation time of 0.64 eV at the high temperatures and its dielectric strength revealed a possible defect cross-over at T c = 190 K. Far below this temperature the activation energy was 0.38 eV, that is about half of that necessary for a pair of ion defects to form. In comparison with the results of other authors, a lower concentration of ionic defects, or possibly of Bjerrum–ion aggregates, was deduced to occur in our crystals. Inert-gas host molecules were proposed as a possible origin of the two other spectra, having relaxation times shorter than the “Debye spectrum” and energies of 0.33 eV and 0.37 eV. Moreover the 0.33 eV spectrum, whose dielectric strength appears at a temperature below T c, might alternatively be related to the cross-over of the “Debye spectrum”.

Anisotropic Dielectric Relaxation in Single Crystal H$_{2}$O Ice Ih from 80-250 K

“…The theories of the TSD currents 17,22,25,26 , static conductivity 1,2,27,28 , and dielectric relaxation time 22,25,[29][30][31] for ice are well documented and have shown conformity with experiment.…”

“…For ice, the dielectric relaxation time depends on the temperature and purity of the sample. 1,34 The Debye relaxation time has been theoretically evaluated and extended by Kauzmann 29 from Eyring's rate-process theory 30 and applied to ice by Johari and Jones 22 and Loria, et al 25 The general form of the dielectric relaxation time is given by…”

“…For the purposes of this manuscript τ 0 , E τ , and k B can all be treated as constants, to first-order. 25 Because of its reliability in measuring τ D on the order of hours or days, the voltage-step technique 22,31 was used to determine the τ D of ice at low T . The theory of this technique is explained as follows.…”