MAGNETIC PHASES IN UNIGE

Antiferromagnetic ordering in UNiGe below 50 K has been confirmed by s pecific-heat, magnetization, electrical resistivity and neutron-diffra ction studies. Between 41.5 and 50 K, an incommensurate AF phase with q=(0,1/2,-1/2)+/-delta(0,1,1), delta=0.141 (at 46 K) appears, whereas a commensurate AF structure with q=(0,1/2,1/2) sets on below 41.5 K. I n magnetic fields (parallel to the c-axis) sufficient for a metamagnet ic transition both the structures are transformed to a phase with q=(0 ,1/3,1/3) yielding a non-zero magnetization M approximate to 1/3M(s).