Magnetomigration effect during the annealing of granular cobalt-copper films

We have studied the influence of long-term low-temperature (220$^\circ$C) annealing in a constant magnetic field on the composition of granular cobalt-copper (Co–Cu) alloy films deposited by the ion-plasma method onto hot silicon substrates. The magnetic-field strength at the film surface was 500–550 Oe, and the field lines were parallel to the substrate plane. The phenomenon of magnetomigration of the main alloy components in the film during annealing has been observed. Cobalt and copper, possessing different magnetic properties, migrated in the opposite directions in the depth of the film. Depending on the duration of annealing, this effect leads in some cases to separation of the film into two sublayers with different compositions.