Spectral response from modulus time domain data of disordered materials

Abstract

The electric response of the glass-forming glycerol and crystalline ionic conductor Li0.18La0.61TiO3 is probed by modulus time domain measurements. A capacity correction algorithm is proposed to overcome the low capacitance limit of the technique. This method allows to Fourier-transform time domain data yielding undisturbed permittivity spectra. The algorithm is checked first in glycerol, where the dielectric data recorded in frequency and time domain show an overlap of several decades. It is also applied to match the dielectric data of the crystalline ionic conductor Li0.18La0.61TiO3 from modulus time domain with overlapping frequency domain data, forming data sets covering 11 decades in frequency. The extension of the electrical characterization to low frequencies allows the detection of an Arrhenius behavior for the dc ionic conductivity at low temperatures, in disagreement with previous analysis in terms of Vogel-Fulcher-Tammann laws.