Impedance spectroscopy studies of K2SO4 in the intermediate temperature regime
Artikel i vetenskaplig tidskrift, 2005
Impedance spectroscopy measurements of K2SO4 have been carried out from 5 Hz to 13 MHz over the temperature range 403-782 T. The plots of corrected imaginary part of permittivity, epsilon", and its real part epsilon' vs. frequency clearly show a new dielectric relaxation around epsilon") = 1.4 X 10(4) Hz at 403 degrees C, which shifts to higher frequencies (similar to 1 MHz) as the temperatures increases. The fma (calculated from the peak position of epsilon") vs. reciprocal T shows an activated relaxation process over the temperature range 403-600 T with activation energy E-a = 1.02 eV, which is close to that derived from the dc-conductivity, E-a = 1.15 eV. We suggest that the observed dielectric relaxation could be produced by the K+ jump and SO4- reorientation that cause distortion and change the local lattice polarizability inducing dipoles like KSO4-.