GD-155 MOSSBAUER-EFFECT IN SEVERAL BANISN3-TYPE COMPOUNDS

We have investigated the magnetic properties and the Gd-155 Mossbauer spectra of several BaNiSn3-type rare earth compounds comprising GdCoSi 3, GdNiGa3, GdCuGa3 and GdCuAl3. All four compounds were found to orde r antiferromagnetically at low temperatures. From the quadrupole split ting obtained from fitting the Gd-155 Mossbauer spectra, we derived va lues for the electric field gradient V-zz at the nuclear Gd site. The values of V-zz were found to be positive and to increase in the sequen ce mentioned above. This behaviour is discussed in terms of on-site va lence electron asphericity contributions to V-zz.