MICROSTRUCTURE AND GIANT MAGNETORESISTANCE IN CO AG FILMS/

Giant magnetoresistance values have been observed in Co/Ag composite f ilms. The largest change in magnetoresistance values were measured in the as-deposited Ag-rich samples with maxima of the order of 30%, at 3 0K. X-ray diffraction and electron microscope studies indicate a unifo rm fcc structure with an apparent composition dependent lattice parame ter. However, high resolution electron micrographs provide the first e vidence of Co clustering in an Ag matrix via the observation of the la ttice spacing which dearly corresponds to the (200) line of fcc Co. We believe that the GMR is due to interfacial scattering from these dust ers.