Interlayer Coupling Through Cu Spacer and Its Unique Temperature Dependency in Spin Valve Films With Co $_{1 - x}$ Fe

The spin valve films with the insertion of a nano-oxide-layer are expected as nano-constriction SV MR devices such as nano-contact MR. However, the nature of those magnetic coupling, such as the exchange bias and interlayer coupling in SV films with the insertion of a NOL have been not well discussed. In this paper, the interlayer coupling field through Cu spacer and its temperature dependency in SVs with Co_1-xFe_x-NOL and Co_1-xFe_x/Cr-NOL are studied to confirm the influence of the insertion of NOL into SV films. In the case of the SVs with Co_0.9Fe_0.1-NOL and Co_0.9Fe_0.1/Cr-NOL, negative interlayer coupling field increases with decreasing temperature in spite of the strength of the Neel coupling of those are almost same with the full metal SV at room temperature. It suggests that the antiferromagnetic interlayer coupling appears by the insertion of NOL into the SVs even though the rough interface. From the result of the temperature dependencies of H_in for each sample, it is considered that the phase of the antiferromagnetic interlayer coupling which related the intensity is varied by the insertion of NOL into the SVs.