Analysis of the power-law response in the fractal dielectric model by thermally stimulated currents and frequency spectroscopy

Abstract

Dielectric properties of a structurally disordered insulator were investigated in the framework of a theoretical model. The model consists of a self-similar structure composed of Debye relaxators which describes a system with a wide distribution of relaxation times that exhibits power-law relaxation at high frequencies in constant temperature measurements. The analysis of the correspondent behavior in a thermally stimulated depolarization experiment shows that the current in the low temperature side of the depolarization peak displays a power-law dependence on heating rate which is a consequence of the self-similar property of the system. The fractionary power-law is related to the fractal dimension by a=2(1−D/3). Therefore the analysis establishes the correlation between isothermal and nonisothermal measurements in dielectric materials that exhibit quasiuniversal nonexponential relaxation.