Ac conductivity of strontium vanadate semiconducting glasses

We have studied the ac conductivity of several compositions of strontium vanadate semiconducting glasses in the frequency range 10 Hz-2 MHz and in the temperature range 80-450 K. We have analysed the experimental results in the framework of the quantum tunnelling and classical hopping models. We observe that tunnelling of the overlapping large polarons is the most suitable mechanism for the ac conductivity of the strontium vanadate glasses.