Magnetic properties of GdT2Ge2 compounds (T=3d, 4d)

We have studied the magnetic properties of the GdT2Ge2, compounds (T = 3d: Fe, Co, Ni, Cu, 4d: Ru, Ph, Pd) by means of DC susceptibility and high-fiel d free-powder (HFFP) measurements. All compounds investigated were found to order antiferromagnetically at low temperatures. The two-sublattice model, without anisotropy, has been used to obtain experimental values for the in trasublattice coupling constant n(11), and the intersublattice exchange cou pling constant n(12). The values of the intersublattice constants derived f rom the high-field data are in good agreement with those obtained from the temperature dependence of the susceptibility. The variations of n(11) and n (12) across the 3d and 4d series in GdT2Ge2 have been discussed in terms of changes of the lattice parameters, the unit-cell volume V and modification s of the transition metal electron band. (C) 2000 Published by Elsevier Sci ence S,A. All rights reserved.