Giant Magnetoresistance Properties in CoFe/Cu Multilayers

Abstract

Giant magnetoresistance (GMR) of multilayer have a potential application in post spin-valve heads, because these heve a larger magnetoresistance (MR) ratio than spin-valves, and they will be useful in the hard disk drive (HDD) heads. In this study, we investigate the dependence of the GMR properties and nano-structure of Co0.9Fe0.1/Cu multilayers on the materials, thickness of the buffer layer and the thickness of the Cu and CoFe layers. A maximum MR ratio of 20.1% and the resistivity change, Δρ, of 4.5 μΩcm were obtained at a Cu thickness of 21.6Å which is the second antiferromagnetic coupling peak of the interlayer coupling oscillation. Large MR ratio is obtained for the film which has small XRD peak intensity of Cu (111). The orientation of Cu (111) in multilayers was dependent on both the material and the thickness of the buffer layer. The reason of this behavior is that an increase in the roughness of the CoFe/Cu interface, detected by X-ray reflectometry, causes an increase in the area of the interface.