  The electrical conductivity of the switching channel of vanadium dioxide
thin-film sandwich structures is studied over a wide temperature range (15-300
K). It is shown that the electrical resistance of the channel varies with
temperature as R~exp(aT-b/T) in the high-temperature region (above 70 K). The
experimental results are discussed from the viewpoint of the small polaron
hopping conduction theory which takes into account the influence of thermal
lattice vibrations onto the resonance integral.
