MICROSTRUCTURE AND GIANT MAGNETORESISTANCE IN CO/AG FILMS

Giant magnetoresistance values have been observed in Co/Ag composite films. The largest change in magnetoresistance values were measured in the as-deposited Ag-rich samples with maxima of the order of 30%, at 30K. X-ray diffraction and electron microscope studies indicate a uniform fcc structure with an apparent composition dependent lattice parameter. However, high resolution electron micrographs provide the first evidence of Co clustering in an Ag matrix via the observation of the lattice spacing which dearly corresponds to the (200) line of fcc Co. We believe that the GMR is due to interfacial scattering from these dusters.