High current density self-field effects and low-frequency noise in NiFe/Ag GMR multilayers

High current densities (10/sup 6/-10/sup 7/ A/cm/sup 2/) produce magnetic fields which can induce antiparallel magnetic alignment in large (16 /spl mu/m and 8 /spl mu/m) NiFe/Ag thin film multilayer devices. We induce GMR in unannealed devices which normally do not display GMR. We find multiple peaks in the magnetoresistance curves of annealed and unannealed devices. Analysis of the positions and shapes of these magnetoresistance peaks provides a new set of tools for determining the micromagnetic structure of the multilayers. Our magneto-optical Kerr effect data and low frequency noise data correlate with the magnetoresistance peaks and may yield further information about layer-layer interactions and domain structure.