Figures

Figure 1: a) Magnetization curves for two Fe(t_Fe)-Cu(61Å)-Co(55Å)- Cu(36Å) sandwiches grown at 160 °C. The curve indicated by squares is for a t_Fe = 40Å sandwich grown on silicon, and the solid line is for a t_Fe = 16Å sandwich on glass. The plateau region in the t_Fe=40Å curve corresponds to the region where the Fe and Co moments are antialigned.

b) Transverse (applied field perpendicular to current) MR traces for two Fe(t_Fe)-Cu(61Å)-Co(55Å)-Cu(36Å) sandwiches both grown on semi-insulating silicon. The t_Fe=40Å sample is the one whose magnetization curve is shown in a). The t_Fe=16Å sample was deposited at the same time as the t_Fe=16Å sample on glass whose data are shown in a). The MR data for the t_Fe=16Å sample are multiplied by a factor of 10 for clarity. The MR is defined by Dr/r = [r_max - r(H=H_s)]/r(H=0).

Figure 2: Spin-valve MR and anisotropic MR (AMR) versus Fe thickness for a series of 5 Fe(t_Fe)-Cu(61Å)-Co(55Å)-Cu(36Å) sandwiches grown on silicon substrates at 160 ûC. The spin-valve MR is the isotropic component of the total MR. The dashed line is a fit to the AMR data with form AMR = 0.097% + (0.002%/Å)t_Fe.

Figure 3: Spin-valve Dr and r values versus Fe thickness for the samples whose Dr/r is shown in Figure 2. The thickness variation of the MR is clearly dominated by the change in Dr, the numerator of the expression, although the increase in r for low Fe (or Co) thicknesses also plays a role.