I. An oxygen-17 NMR study on oxygen exchange in yttrium barium(2) copper(3) oxygen(7-x). II. Synthesis of transition metal polysulfide complexes from metal powders
Covellite, $\rm Cu\sp{I}\sb2(S\sb2)Cu\sp{II}S$ (T$\sb{\rm c}$ = 1.66 K) and $\rm YBa\sb2Cu\sp{II}\sb2Cu\sp{III}O\sb{7-x}\ (T\sb{c}$ = 92 K) are similar in that both are superconductors containing layered structures and mixed valent copper centers. Our studies on YBa$\sb2$Cu$\sb3$O$\sb{\rm 7-x}$ focused on $\sp{17}$O-labelling of samples of $\rm YBa\sb2 Cu\sb3 O\sb{7-x}$ and the $\sp{17}$O NMR studies of these samples. The $\sp{17}$O-labelling process was carried out using a specially designed glass apparatus. Powder X-ray diffraction and magnetic susceptibility measurements showed that our samples were highly pure. $\sp{17}$O NMR spectroscopy showed that we were able to prepare samples which have uniform and non-uniform distribution of $\sp{17}$O atoms.
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign