The dc conductivity of single crystals of vanadium pentoxide was measured in the three crystallographic directions. The temperature range examined was -165C to 25C. The activation energy of the conduction process was isotropic and found to be .56 ev. The conductivity was anisotropic. Measurements of the Hall effect were attempted with a dc and ac apparatus, but the signal was too low to be observed. However, an upper limit of 71 cu cmcoulomb for the Hall coefficient was calculated, and the upper limit computed for the mobility was .4 sq cmvolt sec. A model is proposed for the conduction mechanism. It suggests that the electrical conduction is a two-step process. The electron is ionized from a V4-oxygen-vacancy center and then moves through the lattice via polaron movement. This model accounts for the isotropy of the activation energy and also the anisotropy of the conductivity. Author
Report on Electrochemistry of Primary Oxide Electrodes.