-Interface effects on the magnetic moment of Co and Cu in CoCu granular alloys

We report on x-ray magnetic circular dichroism experiments performed on Co5Cu95 annealed granular alloys with giant magnetoresistance. Results on the Co-L-2,L-3 edge evidence a direct correlation between the Co orbital and spin magnetic moment and the Co clusters interfacial roughness. On the other hand, we have found dichroism on the Cu-L-2,L-3 edge, revealing an induced magnetic polarization of the Cu interfacial atoms. The magnetic moment of the Cu atoms is mainly of spin character and is ferromagnetically coupled with the Co magnetic moment.