Interdiffusion in the pinned electrode of the exchanged-biased magnetic tunnel junctions

Summary form only given. The pinned electrode of the exchange biased magnetic tunneling junction (MTJ), consisting of Ta/NiFe/IrMn/CoFe/AlO/sub x//Ta layer was annealed at 300/spl deg/C under vacuum to study the extent of interdiffusion within the pinned electrode. In addition, the tunnel barrier layer, AlO/sub x/ was deliberately under- and over-oxidized in the oxygen plasma in order to elucidate the effects of plasma oxidation on the interdiffusion within the thin film stack. A significant amount of Mn diffusion into the AlO/sub x/ layer was observed in the over-oxidized electrode from the compositional depth profiling using Auger Electron Spectroscopy (AES) while the under-oxidized electrode exhibited a minimal amount of Mn diffusion after annealing at 300/spl deg/C. Further interfacial analysis using X-ray Photoelectron Spectroscopy (XPS) proved that the Mn found at the CoFe/AlO/sub x/ interface in the over-oxidized electrode was in the form of MnO/sub 2/ while the Co in the CoFe layer remained unoxidized.