Discrimination between dipolar and space-charge relaxation by thermally stimulated current spectroscopy: application to several alkali-exchanged mordenites

Thermally stimulated current (TSC) spectroscopy is widely used to understan d dielectric relaxation in complex solid systems. However, when these syste ms contain free and bound charges, it appears that TSC spectra exhibit mult icomponent signals, due both to dipolar and to space-charge relaxation. In this work, we propose an experimental method to identify clearly and then s eparate the space-charge contribution from the dipolar current, in ionicall y conducting solids. This method is based on the comparison between global and fractional thermally stimulated current procedures and is applied to an alyse the dielectric response of several alkali-exchanged mordenites (with exchange of Li+, Na+ and K+ for H+).