Dielectric and Mechanical Response of Ice Ih Single Crystals and Its Interpretation

Abstract

After a short introduction of the status quo and of the experimental distinction between continuous distributions of relaxation time and discrete spectra, it is shown that in our best Ice I_h single crystals seven discrete relaxation spectra can be identified in the frequency range from ${\text{8 × 10}}^{\text{−3}}$ to 10⁵ Hz. The experimental determination of the molecular origin of these ``standard'' spectra is the main theme of our investigation. Evidence is provided by the magnitude and temperature dependence of the relaxation times τ and polarization contributions $\mathrm{\Delta \; \kappa \prime }$ of the various spectra and the influence of imperfections, multicrystallinity, and of HF doping on these characteristics. Spectrum 3, representing the normal volume polarization of ice, can be explained satisfactorily by the dipole moments inscribed by field‐directed diffusion of Bjerrum L, D defects into the proton memory system; destruction of the single crystal produces a cheaper L‐D supply, reduction of the diffusion distance, and a new spectrum 3A of internal boundary conduction. The correlation claimed between mechanical and electrical relaxation by L‐, D‐defect action seems erroneous: Mechanical losses and basal glide appear to originate from the formation of Frenkel defect pairs and dislocation transfer. Spectra 0–2 stem from imperfections, spectra 4–6 from charge carriers avoiding the antipolarization memory of the ice and causing space‐charge polarization. The action of HF on polarization and conduction of ice single crystals, as seen by our discrete dielectric spectra analysis, is very different from that previously believed and reported. It is tentatively analyzed for spectra 1–4; mechanical and diffusion effects are also considered. The work is being extended to transconduction and electrode phenomena.