ABINITIO CALCULATION OF MAGNETIC-MOMENTS AND HYPERFINE FIELDS IN Y2FE17Z3 (Z = H, C, N)

The local magnetic moments and hyperfine fields on the crystallographically different Fe and Y sites and on the interstitial atoms Z are calculated for the technologically important hard magnetic compounds Y2Fe17 and Y2Fe17Z3 with Z = H, C, N by means of the local-spin-density approximation and the linear-muffin-tin-orbital theory in atomic-sphere approximation. The competing effects of volume expansion and hybridization between the interstitial atoms and the neighbouring Fe atoms are discussed, and the limitations of the atomic-sphere approximation are elucidated.