METAMAGNETIC TRANSITIONS AND GIANT MAGNETORESISTANCE IN UNIGE

We report on the temperature dependence of the metamagnetic transitions, which occur in UNiGe in magnetic fields applied along the b and c axis. Above the ordering temperature T(N) = 50 K, a strong magnetic and thermal history-dependence is found. Furthermore, the development of a small ferromagnetic component (0.02mu(B)/f.u.) at 4.2 K after releasing the field applied indicates magnetic-history effects also at low temperatures. The presumed irreversibility in the magnetization process at low temperatures is corroborated by irreproducible changes in the magnetoresistance response at 4.2 K. Nevertheless, tentative magnetic phase diagrams have been obtained for both orientations.