Perpendicular giant magnetoresistance of Co/Cu multilayers with fluctuating Co layer thicknesses

J. Mathon has predicted that introducing pseudorandom fluctuations (PRF) in the Co layer thickness could greatly enhance the Current Perpendicular to the Plane (CPP) magnetoresistance (MR) of a Co/Cu superlattice with dimensions comparable to the electron mean-free-path. We have searched for CPP-MR enhancement in sputtered Co/Cu multilayers with Cu layer thicknesses near both the first and second antiferromagnetically coupled peaks in the oscillatory region of the CPP-MR. In both cases, inserting PRF only decreased the CPP-MR.