NONOSCILLATORY MAGNETORESISTANCE IN CO/CU/CO LAYERED STRUCTURES WITH OSCILLATORY COUPLING

Using sputtered thin-film layered structures comprising Si/[8x(20-angstrom Ru/x Cu)]/(30-angstrom Co)/(t(Cu) Cu/30-angstrom Co)/(150-angstrom Fe50Mn50), with x = 8 and 12 angstrom, we demonstrate that the oscillation in the coupling of the two Co layers as the Cu-layer thickness, t(Cu), is varied, is not accompanied by an oscillation in the amplitude of the magnetoresistance. Thus the previously reported oscillation in magnetoresistance in Fe/Cr, Co/Ru, Co/Cr, and Co/Cu multilayers is not a fundamental electronic effect, but a consequence of the inability to vary consistently the angles between the magnetizations of these multilayers.