KERR ROTATION MEASUREMENTS ON AMORPHOUS U-AS-CO THIN-FILMS

Thin films of (U-As)100-xCox alloys are prepared by magnetron sputteri ng over the entire composition range x and the polar Kerr rotation and magnetization are measured. The absolute value of the maximum Kerr ro tation decreases rapidly from -0.48-degrees for Co (x=100) to -0.09-de grees for x=66 at 300 K. A similar decrease is observed at 10 K but at a slightly slower rate. The Kerr rotation as well as the magnetizatio n are negligible at x congruent-to 50, indicating a suppression of the magnetic moments in Co and U, simultaneously. This result is explaine d in terms of filling in the Co 3d conduction band. At x less-than-or- equal-t 30, U develops a magnetic moment at 10 K but Co does not seem to contribute to the magnetization for these compositions.