GD-155 MOSSBAUER-EFFECT AND MAGNETIC-PROPERTIES OF GDMN6GE6

The magnetic properties of GdMn6Ge6 have been studied by magnetic measurements and Gd-155 Mossbauer spectroscopy. The Mn sublattice orders ferromagnetically in high magnetic fields and at high temperatures but in low fields and low temperatures there is a tendency to antiferromagnetic ordering. Antiferromagnetic order was also found in YMn6Ge6. The electric field gradient derived from the quadrupolar splitting of the Gd-155 Mossbauer spectra is substantially larger than in the isotypic compound GdMn6Sn6.