BIAS CURRENT DEPENDENT RESISTANCE PEAKS IN NIFE AG GIANT MAGNETORESISTANCE MULTILAYERS/

We show that thin-film Ni82Fe18/Ag multilayer structures display multi ple peaks in their magnetoresistance curves when biased at current den sities above 10(6) A/cm(2). These peaks appear for annealed and unanne aled structures, and their number is correlated with the number of NiF e layers. At high bias currents, the peak positions shift linearly wit h the internal magnetic field created by the bias current. The peak po sitions 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 i ncreasing temperature. The single-domain magnetic moment mu is estimat ed 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.