ErFe2-H-2 system II. Non-collinear magnetic ordering

The 'fanning' of rare-earth moments has often been conjectured in intermeta llic systems to explain the reduced ordered moment values. The present stud ies on the ErFe2Hx system clearly show that the Fe sites having one nearest -neighbour H atom possess non-collinear magnetic ordering, with their spins along [113], [113], [113] and [113] directions. The effect of a larger num ber of H neighbours on the spin orientation of Fe atoms has also been discu ssed. Field-dependent magnetization studies showing a decrease in magnetiza tion with increase in the field further support non-collinear magnetic orde ring. In view of the strong antiferromagnetic interactions between the Fe a nd Er sublattices, a non-collinearity (or 'fanning') of rare-earth moments is justified. A large reduction in the ordered moment values of Er, with in creasing x, obtained from our neutron diffraction studies, is in agreement with this view.