Regensburg 2016 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

MM: Fachverband Metall- und Materialphysik

MM 14: Transport II: Atomic and ionic transport

MM 14.6: Vortrag

Montag, 7. März 2016, 17:15–17:30, H53

The mechanism of mixed ionic and electronic transport during electro-thermal poling — •Martin Schäfer and Karl-Michael Weitzel — Fachbereich Chemie, Philipps-Universität Marburg

Electro-thermal poling is a technique that allows to investigate and manipulate physical properties of solid electrolytes, e.g. ion conducting glasses, in particular at the sample surface. During the poling experiment, the sample is placed between two ion blocking metal-electrodes and an electric field is applied at elevated temperatures. The charge carriers inside the sample move according to the field and give rise to an ion depletion zone below the anode. Usually, the buildup of the depletion zone is accompanied by the decay of the poling current and by the simultaneous expulsion of the field from the bulk of the sample such that eventually a strong field remains in the depletion zone solely. Here, a calculation based on a Monte-Carlo simulation is presented that describes the mechanism of electro-poling in samples with more than one mobile carrier species. The model explicitly includes the diffusion of two ion species and the electron mobility at electric field strengths beyond the breakdown field strength. The calculations show that for certain ion mobilities, the time evolution of the potential and the current decay occur on significantly different time scales. Diffusion profiles are calculated and compared to experiments from literature. Very good agreement is reached.