An extensive study of the 51V NMR in V02 has been made between 4.2 K and 600 K, particularly laying stress on the analysis of the temperature dependence of the nuclear relaxation rate 1/7. In the metallic (M) phase (r>rt = 340K) an exchange-enhanced Korringa relaxation process for l/Ti is observed and the spin fluctuation effects have been treated within RPA. In the insulating (I) phase (T<Tt), l/TT) cannot be explained from a simple band model and it is proposed that the hopping motion of the self-trapped carriers or excitons are responsible for the relaxation process. The 51V NMR in the substitutional compounds, Vi_*W*02 (0<x<0.075), has also been studied in the M phase in order to obtain further knowledge to the M-I transition. From the RPA analysis, it is shown that the -dependence of the experimental data are in general accord with the nesting model proposed by M. Gupta et al.
ASJC Scopus subject areas
- Physics and Astronomy(all)