MAGNETIC PHASE-DIAGRAMS OF UNIGE

UNiGe undergoes two magnetic transitions in zero held. Here, the magne tic diagrams of UNiGe for B parallel to b and B parallel to c are repo rted. We performed temperature scans of the magnetization in static ma gnetic fields up to 19.5 T applied along the b and c axes. For both or ientations three magnetic phases have been identified in the B-T diagr ams. We confirmed the previously reported phase boundaries for B paral lel to c, and in addition we determined the location of the phase boun daries for B parallel to b. We discuss a possible relationship of the two zero-field antiferromagnetic phases (commensurate: T < 42 K; incom mensurate: 42 K < T < 50 K) and the field-induced phase, which at low temperatures, occurs between 18 and 25 T or 4 and 10 T for B parallel to b or B parallel to c, respectively. Finally, we discuss the field d ependence of the electronic contribution gamma to the specific heat fo r B parallel to c up to 17.5 T, and we find that its field dependence is similar to the one found in more itinerant uranium compounds. (C) 1 998 Elsevier Science B.V. All rights reserved.