Studies of anisotropic and giant magnetoresistance in Co/Cu(111) epitaxial multilayers

Abstract

Co/Cu͑111͒ multilayers, ͓Co͑17 Å͒/Cu͑8 ÅϽt Cu Ͻ14 Å͔͒ 30 , have been prepared on Co͑70 Å͒ buffer layers on Al 2 O 3 ͑0001͒ substrates by molecular beam epitaxy. From the longitudinal and transverse magnetoresistance ͑MR͒ measurements, it is observed that MRs consist of two components with a small anisotropic MR ͑Ͻ2%͒ component at low field sitting on top of the giant MR ͑up to 22%͒ component at higher field. The AMR effect strongly correlates with the abundance of hcp stacking of Co, which tends to decrease with the increasing of Cu spacer thickness. The AMR saturation fields ͑1-3 kOe͒ coincides with those of the magnetization. It is suggested that the observed AMR effect is due to scattering from the hcp-phase Co layers in the multilayers. This together with the large saturation field ͑30-40 kOe͒ obtained from the entire MR curves indicate that the observed GMR effect may result from the Co-Cu interfacial spin-dependent scattering.

Nanofabrication of integrated magnetoelectronic devices using patterned self-assembled copolymer templates

“…7,8 In recent studies, the coexistence of GMR and AMR has been reported in multilayers and multilayered nanowires. 6,[9][10][11] Dips in the MR data, similar to that shown in Fig. 2͑c͒, have also been seen.…”

Temperature dependence of the magnetoresistance in Co/Re superlattices onAl2O3Charlton1, Lederman2 2001Phys. Rev. B

“…Neither the GMR, discovered in the late 1980's, 2 or the AMR, which was studied extensively in the 1930's, 3 are new effects, but only relatively recently have these two effects been studied in the same system. Some previously studied systems with both AMR and GMR include Co/Cr, 1 Fe/Cr, 4,5 Co/Ru, 6 Co/Cu, 7,8 and Permalloy/Cu ͑Ref. 9͒ multilayers.…”

Nanoscale characterisation and magnetic properties of Co81Cu19/Cu multilayer nanowires

“…37, 38 It is therefore believed that this observation also reveals the intrinsic reason why the GMR effect 75 of the specimens prepared by electrodeposition method is universally smaller than those of high-vacuum sputtering method or molecular beam epitaxy (MBE) method. 26,27 The magnetic properties of the Co 81 Cu 19 /Cu multilayer nanowires were measured by a VSM with the applied field at 80 different angles (θ) between external field and nanowire length axis. Figure 7a shows two hysteresis curves of the Co 81 Cu 19 /Cu multilayer nanowire arrays measured at room temperature with an applied field up to 1.6 T at 0° and 90° angles.…”

“…26, 27 A number of published 70 work were devoted to figure out the intrinsic reasons between the GMR effect, magnetic properties of PD Co-Cu multilayer structures and their nanoscale characterisation, including morphology, chemistry, structure, interfaces and grain sizes. 26,27 However, the systemically nanoscale characterisation of 1D ED 75 …”