A study of magnetic coupling in GdT2Si2 compounds (T = transition metal)

The magnetic coupling in the GdT2Si2 (T=transition metal) antiferromagnetic compounds is studied by means of DC susceptibility and high-field free-powder (HFFP) measurements. In most compounds, the experimental results can be described in the framework of a two-sublattice model without anisotropy. From this analysis, an intrasublattice exchange coupling constant, n(11), and an intersublattice exchange coupling constant, n(12), are obtained. The exchange couplings are discussed in terms of the change of the lattice parameters, the volume V and the filling of the transition metal electron band. The apparently reduced value of the moment per Gd atom in the forced ferromagnetic configuration is attributed to a reduction of the on-site 5d-moment and a possible negative polarisation of the other non-4f electrons. (C) 1997 Elsevier Science S.A.