Ionic conduction and dynamical regimes in silver phosphate glasses

Dielectric measurements on ion conducting silver metaphosphate glasses, pure and doped with silver sulphide or silver sulphate, have been performed in the microwave frequency region up to 60 GHz in a wide temperature range between 77 and 413 K. With the current extension of previous measurements, a frequency range larger than 10 decades has been investigated and several distinct conductivity regimes have been observed. Above the low frequency dc conductivity value, the progressive increase of conductivity with frequency has been found to obey first a power law with exponent p∼2/3 and later another power law with exponent q∼4/3, nearly independent of temperature and of composition. In the low temperature region a nearly constant loss contribution to the conductivity has been also detected.