EFFECT OF INTERSTITIAL HYDROGEN AND NITROGEN ON THE MAGNETOCRYSTALLINE ANISOTROPY OF R2FE17 (R = TB, DY, HO, ER)

The magnetocrystalline anisotropies of R2Fe17 (R=Tb,Dy,Ho and Er) and of the nitrides and hydrides of these compounds are studied by analysi ng the hard and the easy magnetization curves of magnetically aligned samples in the temperature range 80-300 K. The effects of the hydrogen and the nitrogen atoms on the rare earth sublattice anisotropy are fo und to be opposite. It is observed that, in contrast to nitrogenation, hydrogenation leads to an easy axis type R sublattice anisotropy for R ions with negative Stevens factor alpha(2) (Tb, Dy and Ho). An easy- plane to easy-cone transition is detected for Dy2Fe17Hx (x=3 and 5). T he magnetic structures of Tb2Fe17Hx (x=3 and 5) are possibly of the ea sy-cone type at room temperature. (C) 1997 Elsevier Science S.A.