Scaling properties of thermally stimulated currents in disordered systems

We investigate the non-isothermal manifestation of Jonscher's universal dyn amic response in terms of thermally stimulated depolarization (TSD) current s. We show that relaxation processes which display power-law behavior and w hich obey in addition the time-temperature superposition principle are adeq uately described by a new TSD scheme which consists of a fractional power o f the reduced time. The initial current of TSD peaks in disordered material s such as ionically conducting glasses, polymers, and amorphous semiconduct ors, is. found to exhibit two major aspects of remarkable generality: a dep endence on heating rate (which is unpaired in the classical model), and an effective activation energy with a value of aE, where E is the activation e nergy for the scaling time and a is a fractional exponent. The underlying l ink between these results and the self-scaling property of the relaxation f unction is pointed out. (C) 1999 Elsevier Science B.V. All rights reserved.