Vanadium Nuclei Research Articles

Electron Spin Resonance Study of Partially Reduced Vanadium Pentoxide

Single crystals of partially reduced vanadium pentoxide have been prepared in the form CuxV2O5 with 0≤x≤0.040, and two distinct types of paramagnetic species have been observed by ESR techniques. Neither of these species is associated with copper (II). For 0≤x≤0.0058, the dominant species is one in which the electron is localized, the hyperfine structure indicating interaction with two equivalent vanadium nuclei. This center is apparently identical to that observable in ordinary laboratory reagent grades of vanadium pentoxide. In addition, for 0.0078≤x, the spectra show a superimposed single narrow line of total width 10–20 G. The g tensor of this species shows that it is still primarily associated with the vanadium sites, but the lack of hyperfine structure indicates a considerable mobility. The latter species is not observed in ``pure'' vanadium pentoxide but is very similar to the mobile species observed in vanadium bronzes.