Annealing temperature dependence on magnetoresistance of single and dual specular spin valve

We studied the changes of magnetoresistance ratio (MR ratio), exchange bias field (Hex), and microstructure with annealing in conventional, specular, and dual specular spin valves. MR ratio of conventional spin valve was 7.88% and that of specular spin valve was 11.8% at their optimal annealing conditions. Conventional spin valve had less thermal stability than specular spin valve due to the diffusion mainly of Mn at between 200 and 305 °C. Exchange bias field of both samples was improved rapidly with increasing temperature. Dual specular spin valve showed higher MR ratio than single specular spin valve due to two nano-oxide layers (NOLs) in the top- and bottom-pinned layers.