Electrical conductivity and dielectric properties of some vanadium–strontium–iron unconventional oxide glasses

An unconventional oxide glass system of the composition (80 − x)%V2O5·x%SrO·20%FeO (0 ≤ x ≤ 40) was prepared by the press-quenching technique. The electrical conductivity (σdc and σac) was measured in the temperature range from 308 to 588 K. σdc was found to follow a mixed conduction of both small polaron hopping (SPH) and variable range hopping (VRH) mechanisms up to 418 K. Above this temperature σdc follows SPH conduction mechanism only. σac was determined at four frequencies (102, 103, 104, 105 Hz). It was found that the correlated barrier hopping (CBH) was the applicable mechanism, and the exponent factor (s) varied from 0.1 to 0.83. The theoretical fitting between the proposed models and the experimental data showed good agreement. σdc and σac were found to decrease with the increase of SrO content, and both the dielectric constant ɛ′ and loss ɛ″ were found to increase with temperature and decrease with the frequency.