THE INFLUENCE OF INTERSTITIAL N, C AND H-ATOMS ON THE HYPERFINE FIELDS AT THE YTTRIUM AND COBALT SITES IN Y2CO17

The spin echo nuclear magnetic resonance spectra of Y2Co17Ax (A = N, C, H) are presented. On the basis of the satellite pattern of the Y-89 spectra, we have deduced that N and C atoms occupy the 9e sites (rhombohedral compounds) or 6h sites (hexagonal compounds) around the yttrium site. A decrease in the hyperfine fields at the yttrium and cobalt sites caused by neighbouring interstitial atoms is observed, with a magnitude dependent on the site and the type of interstitial atom. The effect is discussed in terms of the influence of N, C and H atoms on the local electronic structure at the yttrium and cobalt sites and compared with the effect observed in the RE2Fe17-based compounds (RE, rare earth).