The Magnetic Properties of Uranium and Uranium-Iron Alloys

Measurements have been made of the magnetic susceptibility of fairly pure uranium and of 5 and 10 atomic per cent alloys of iron with uranium. Using a modification of the Curie method, with special pole-pieces and electromagnetic dynamometer control, the specimens were found to be paramagnetic with no trace of ferromagnetism in the temperature range 20° to 350° C At 20° C. the susceptibility of pure uranium is +1.740 × 10 -6 E.M.U. per gm., increasing to +1.804 × 10 -6 at 350° C.; the results fit the equation χ U = 32 × 10 -11 T +1.564 × 10 -6 +24.0 × 10 -6 / T . Assuming that the iron is present in form of the compound U 6 .Fe, it is found that the latter has a susceptibility of +2.036 × 10 -6 E.M.U. per gm. at 20° C., which remains practically constant with temperature.