MAGNETIC-SUSCEPTIBILITY OF AUFE ALLOY-FILMS

AuFe alloys containing 2 to 12 at.% Fe are produced by quench condensation from the vapour phase onto a cold substrate. The paramagnetic susceptibility chi is measured in situ in an AC magnetic field of 22 Oe and 1100 Hz at temperatures between 2.5K and 150K. The paramagnetic Curie temperature, the effective magnetic moment and the temperature Tf of the maximum of chi depend on the Fe concentration and on annealing, Tf increases with annealing. Films annealed at 1100K show nearly the same Tf values as bulk AuFe. Most of the increase of Tf with annealing can be attributed to the rising mean free path of the conduction electrons. A rounded peak of chi is observed for films annealed at 80K; a sharper peak after annealing at 295K or 1100K. Small DC fields reduce only the susceptibility peak of films annealed at 295K or at higher temperature. A sharp peak of chi and its reduction in a DC field is apparently due to Fe clusters produced during annealing.