Comparative study of giant magnetoresistance in CoZr/Cu and Co/Cu multilayers

Buffer effect on GMR in thin Co/Cu multilayers

“…Moreover, the rate of decrease of the resistance (R) of Cu and Co buffer-based MLs with field was similar to that on glass, initially being rapid and then decreasing with increasing field. This kind of triangular loop has been previously attributed to incomplete AF coupling [13,14]. Similar R-H curves were observed for Ta and Al buffer-based MLs but with much smaller GMR and J magnitude as shown in Table 1.…”

“…Nominal composition [Co(1.1 nm/Cu(0.9 nm)] ×25 MLs were deposited on 8 nm thick buffer layers of Fe, Cr, Al, Ta, Co or Cu on a glass substrate at room temperature by RF diode sputtering as described elsewhere [13]. The films were prepared from high-purity targets.…”

Enhancement of magnetoresistance sensitivity in Co/Cu/NiFe trilayers by softening the Co hard layer

“…In those multilayer systems, the GMR effect is attributed to the antiferromagnetic coupling between the adjacent magnetic layers across the nonmagnetic layers. However, it is the antiferromagnetic coupling that results in a high saturation field for the multilayers and hence a low magnetoresistance (MR) sensitivity [4]. This limits their applications for use in MR sensors and high-density read-out heads [5].…”

“…In addition to this, however, MR sensitivity is of significant importance in terms of the applications in sensors, high-density read-out heads and other magnetic storage technology. Hence, much interest has been focused on the improvement of sensitivity for the multilayers [4,14,15]. Among those researches, it has been reported that the MR sensitivity for the Co/Cu multilayers can be improved by replacing the Co layer with a soft magnetic layer, such as CoZr/Cu [4] and NiFeCo/ Cu multilayers [15], which stimulated us to study the change of the MR sensitivity in hard/Cu/soft trilayers by changing the coercivity of the hard layer.…”