Eur. Phys. J. B 33, 183-191 (2003)
https://doi.org/10.1140/epjb/e2003-00155-x

Covalent magnetism in the RFe₆Ge₆ series

¹ Laboratoire de Chimie du Solide Minéral, Université Henri Poincaré-Nancy I (Associé au CNRS (UMR 7555)) , BP 239, 54506 Vandoeuvre-les-Nancy Cedex, France
² Faculty of Physics and Nuclear Techniques, University of Mining and Metallurgy, Al. Mickiewicza 30, 30-059 Crakow, Poland

Corresponding author: ^a Thomas.Mazet@lcsm.uhp-nancy.fr

Received: 20 December 2002
Published online: 4 June 2003

Abstract

The electronic structure of the RFe₆Ge₆ compounds (R = Sc, Lu, Ti, Zr, Hf and Nb) of HfFe₆Ge₆-type structure has been studied using the muffin-tin Korringa-Kohn-Rostoker method in a non-relativistic approach. The chemical bonding is analyzed based on the l-decomposed site projected densities of states. Spin-dependent changes in the R nd- Fe 3d covalent bond are shown to be responsible for the experimentally observed rise in the Fe moment and hyperfine field upon increasing the R valency. The limited quantitative agreement between theoretical and experimental values is interpreted as being due to a non-negligible orbital moment and to a significant asphericity in the spin density at the iron site. The theoretical results also forecast a strong increase of the Ge(2e) transferred hyperfine field with the R valency.