Enhancement of the magnetoresistance by inserting a nano oxide layer in Mn-Ir bottom spin valve

Si/Ta/Ni-Fe/Mn-Ir/Co-Fe/NOL/Co-Fe/Cu/Co-Fe/capping bottom specular spin valves were prepared by using the DC magnetron sputtering method. The specular spin valve (with nano oxide layer (NOL)) exhibited higher MR% (Magnetoresistance) ratio and H-ex (exchange biased field) than those of a conventional spin valve (without NOL). Also, the conventional spin valve showed a higher H-in (interlayer coupling field) than the specular spin valve. RBS (Rutherford back scattering) and TEM (Transmission electron microscopy) analyses indicated that thickness of NOL was about 2 nm. The thermal aging experiment showed that the Ta capping layer was more stable than the Al capping layer.