The dc electrical conductivity of iron phosphate glasses

The electrical conductivity of several phosphate glasses was studied over a wide temperature range. Contents of several metals (Fe, Na, Cs, K) were changed in an attempt to study the influence of composition on the electrical properties. Electrons are shown to be the dominant charge carriers. At room temperature, the dc conductivity is typically 10−12–10−10 Ω−1 cm−1 with an activation energy of 0.55 eV. Over a temperature range from 150 to 400 K the conductivity is described by the variable range hopping mechanism. Several common problems and ambiguities in the analysis of the dc electrical conductivity are discussed briefly. The data and interpretation are compared to other published results.