Magnetization processes and magnetoresistance in Co/Cu multilayers as a function of the Cu layer thickness.

We have studied Co(15 A)/Cu(t) multilayers with nominal Cu spacer layer thicknesses of 7, 8, 9, and 10 A. For multilayers with identical dimensions, transport measurements showed that the introduction of oxygen during growth increased the magnetoresistance while transmission electron microscopy revealed the effect of the oxygen bleed on the microstructure was reduced grain size, suppression of the Cohcp phase, and reduced texturing. Lorentz microscopy was used to determine the angle between magnetization vectors in adjacent magnetic layers and the values so deduced were found to correlate well with the variation of magnetoresistance within the multilayer sets.