GD-155 MOSSBAUER-EFFECT AND MAGNETIC-PROPERTIES OF TERNARY RARE-EARTH COMPOUNDS OF THE TYPE RT2GE2 (T-EQUIVALENT-TO-3D, 4D)

We investigated the magnetic properties and the Gd-155 Mossbauer spectra of rare earth ternaries of the type RT2Ge2 (T=3d, 4d). The electric field gradient V(zz) derived from the quadrupole splitting of the Mossbauer spectra gives rise to a sign change when passing across the 3d and 4d series. This behaviour was explained in terms of decreasing hybridization between the Gd valence electron states and the d electron states of the T atoms, as already reported previously for the corresponding silicides. The sign of V(zz) was shown to be strongly correlated with the macroscopic magnetic anisotropy behaviour of the series of compounds RT2Ge2.