High field conduction in CdF2 crystals

Abstract

The electrical conduction in pure CdF2 crystals is studied between 80 and 300 °K under electric fields from 10 to 104 V/cm. The U–I characteristic shows an initially linear behaviour, followed by a non-linear trend, where the temperature of the sample increases considerably. Under high voltage excitations a “forming” process takes place, and changes of the electrical properties are observed. The “forming” seems connected to an electrolytic effect for which large zones of metallic Cd are formed in the crystal. As a consequence of the “forming”, switching events take place also at low voltage values. On etudie la conduction electrique dans les cristaux de CdF2 entre 80 et 300 °K en champs electriques qui vont de 10 a 104 V/cm. La variation de la tension par rapport a la courant est initialment lineaire, suivi par un trait qui n'est pas lineaire, ou la temperature de l'echantillon augmente considerablement. Apres une excitation a haute tension on a un proces de “forming” qui changes les proprietes electriques du cristal. Le “forming” semble lie a un effect electrolytique et, en consequence, on a dans le cristal la creation des zones de Cd metallique. Apres avoir realise le “forming”, on a des effects de “switching” měme pour petites valeurs de la tension.