Bias current dependent resistance peaks in NiFe/Ag giant magnetoresistance multilayers

We show that thin-film Ni82Fe18/Ag multilayer structures display multiple peaks in their magnetoresistance curves when biased at current densities above 10(6) A/cm(2). These peaks appear for annealed and unannealed structures, and their number is correlated with the number of NiFe layers. At high bias currents, the peak positions shift linearly with the internal magnetic field created by the bias current. The peak positions extrapolate to nonzero fields at zero bias currents, providing an upper bound on the magnetic layer-layer coupling strength of J(0) approximate to 10(-20) J (k(B)x700 K). The peak positions do not shift with temperature over the range 200-375 K; their widths narrow with increasing temperature. The single-domain magnetic moment mu is estimated as 10(-17) J/T (10(6) mu(B)) from the peak widths of similar to 0.8 kA/m. (C) 1996 American Institute of Physics.