Formation of CCP-NOL in CPP-GMR spin valve structure for the enhancement of magnetoresistance

Abstract For the MR enhancement in current perpendicular to plane-giant magetoresistance spin valve (CPP-GMR SV), a current-confined path—nano-oxide layer (CCP-NOL)—AlO x was formed on the Cu spacer of half SV structure. In order to form effective current-confining paths, an ultra-thin AlO x layer was deposited on a Cu spacer layer by O 2 reactive sputtering of Al with infra-red (IR) heat treatment on the substrate, and that enable to form an island-structured insulating AlO x layer having holes between AlO x islands. By controlling PO 2 and substrate temperature in the NOL deposition, AlO x layer formation without an oxidizing bottom layer could be achieved.