Current-perpendicular spin-valves with partially oxidized magnetic layers for ultrahigh-density magnetic recording

In this paper, by sputter deposition we have prepared single-type CPP spin valves, whose basic structure was buffer/PdPtMn/CoFeB/Ru/CoFeB/Cu/CuFeB/Cu/Cap; the MR ratio of the basic one is 0.6%. The NOLs inserted in the spin valves were formed by the natural oxidization. The resistance was measured using standard four-point probe method at room temperature. Our result show that the GMR enhancement by the NOL strongly depends on the material used, the position, and the thickness. It is also found that the GMR enhancement by the NOL is remarkably material dependent. From the magnetization measurements of the naturally-oxidized thick magnetic layers, we deduced that the oxidized-layer thickness is about 1 mm. These properties of the CPP spin valves with the POML are in an applicable level for the read sensor over 150 Gbit/in/sup 2/ recording density.