Low temperature magnetoresistance of upt3, u3fe and u6co

The transverse magnetoresistance खॡ(T, H)蠁ॡ(T, H)-ॡ(T, 0) has been measured at fixed temperatures in the range 0.5K\leqslant T\leqslant 40K as a function of magnetic field H\leqslant 15T for polycrystalline samples of U6Fe and U6Co, and a single crystal of UPt3 (\overrightarrowH||\overrightarrowa and\overrightarrowH||\overrightarrowc,\overrightarrowJ||\overrightarrowb). The sign of खॡ(T, H) changes from positive to negative as T increases through 蝤25K for U6Fe and U6Co, and\i蝤18K for UPt3. At low temperatures the data obey a novel universal form खॡ=AH2/BCH for all three materials, where A and B are T- and H-independent constants. Such behavior is postulated as typical of materials entering a heavy Fermi liquid state at low temperatures.