Effect of the CoZr/Cu interface quality on the magnetoresistance behavior in a spin-valve sandwich (CoZr/Cu/Co)

Abstract The magnetoresistance (MR) and the saturation resistivity (ρs) are investigated at 300 K in [ Co 98 Zr 2 (t CoZr ( A ))/ Cu (28 A )/ Co (25 A )] thin films grown by RF diode sputtering. The highest value of transverse MR is obtained along the easy axis and the MR curve was saturated in a magnetic field of 100 Oe at room temperature. X-ray diffraction measurements (XRD) at low angles point out clearly the important interfacial roughness increase observed in magnetic structures with CoZr magnetic layers compared to (Co/Cu) basic multilayers. The MR behavior versus the CoZr magnetic layer thickness (tCoZr) exhibits a maximum (≈3.6%) at t CoZr =30 A , over which a significant decrease is observed. ρs decreases with increasing tCoZr up to 30 A, and increases with increasing thickness toward the value of the measured CoZr thicker layer ( ≈40 μΩ cm ). The representation of the CoZr/Cu interface by a mixed zone in the Johnson–Camley semi-classical model reproduces well the experimental results of MR and ρs versus tCoZr, confirming thus the important role of interface quality on the electronic transport properties.