The Hall effect in vitreous 80V₂O₅—20P₂O₅

Abstract

Conductivity, Hall effect and thermopower measurements have been made on vitreous 80V₂O₅—20P₂O₅ in the temperature range 320–500 K. The Hall mobility μ_H shows a strong dependence on temperature with an activation energy (0·2 eV) which is almost half that of the conductivity (0·44 eV). This result is not in agreement with small-polaron theory, according to which the ratio of the activation energy of μ_H to that of the conductivity is expected to be less than one-third. The value of μ_H at room temperature was found to be approximately 3 × 10⁻⁴cm²V⁻¹s⁻¹.