AN NMR-STUDY OF SUPERCONDUCTING ND2CUO3.8F0.2

A nuclear magnetic resonance (NMR) study was carried out to investigat e the magnetic properties of a polycrystalline sample of superconducti ng Nd2CuO3.8F0.2. It was found that both the shift and the width of th e F-19-NMR line decreased as temperature increased from 4.2 to 200 K. Since there existed no indications of peak splits at any temperature, all the F ions were considered to be located in one of the two oxygen sites, i.e., not in both. The Cu-NMR spectra were quite similar to tho se reported for Nd2-yCeyCuO4. In addition, the frequency spectra in ze ro field at 1.3 K indicated that the Nd2CuO4 phase was absent but an u nknown metallic and ''antiferromagnetic'' phase existed, as previously reported for Nd1.85Ce0.15CuO4.