Dielectric breakdown by electrically induced chemical decomposition

Abstract

Experimental observations and our interpretation of electrical current instabilities in single crystals of ionic metal azides are described here. The subsequent insulation breakdown occurs over wide ranges of fields and delay times. The fields, at room temperature, are of the order MV m⁻¹ or lower, and are 2–3 orders of magnitude smaller than the usual dielectric strength found in a homogeneous bulk solid. The breakdown is strongly time dependent and the delay after the application of the field can be up to a few days. We suggest for this low-field long-delay breakdown an ‘electrochemical’ mechanism which seems not to have been envisaged before.