GIANT MAGNETORESISTANCE IN HETEROGENEOUS CU-CO AND AG-CO ALLOY-FILMS

Giant magnetoresistance in sputtered single films of Cu-Co and Ag-Co h eterogeneous alloys is discussed. The films consist of Co-rich precipi tates in a nonferromagnetic matrix. The Ag-Co films have higher DELTAr ho/rho and DELTArho values than the Cu-Co films, possibly due to less Co dissolved in the Ag matrix. DELTArho scales inversely with precipit ate particle size, implying that Co-rich clusters less-than-or-equal-t o 20 angstrom diameter may be most effective for spin dependent scatte ring. This trend of the data and a phenomenological model suggest that interfacial spin dependent scattering is significantly stronger than the scattering within the Co-rich particles.