Аннотации:
The first observations of NMR and NQR of both isotopes135Ba and134Ba in isotopically enriched samples of YBa2Cu3Oy with oxygen concentrations y=6.0, 6.2, and 7.0 are described. The pure NQR frequencies and asymmetry parameter are in good agreement with theoretical predictions. The temperature dependence of the NQR frequency of Ba for y=7 is qualitatively similar to that for Cu(2) but much stronger. The temperature dependence of the longitudinal and transverse relaxation times opens new questions. © 1992 Springer.