SYSTEMATICS OF MAGNETIC HYPERFINE FIELDS AT DILUTED IMPURITIES IN FERROMAGNETIC RARE-EARTH COMPOUNDS GDX (X = ZN AND CD) - A THEORETICAL-STUDY

The hyperfine fields at 3d transition impurities and at non-magnetic ( s-p and noble) impurities in ferromagnetic GdZn and GdCd are theoretic ally discussed in the framework of an 'effective' Gd host. The observe d general trend of the measured hyperfine fields is well reproduced by our model calculations. The calculated local moments at Sc and Ni imp urities in these intermetallics are very small, whereas in the case of Mn and Fe impurities one gets a finite moment of about 1.1 mu(B) and 0.8 mu(B), respectively, which couples antiferromagnetically with the host Gd moments in a quite good agreement with experimental data. (C) 1998 Elsevier Science B.V. All rights reserved.