Suppression of interlayer coupling and enhancement of magnetoresistance in spin valves with oxide layer

The interlayer coupling field (H-int) between the free and pinned ferromagnetic (FM) layers in an exchange-biased spin valve deposited by magnetron sputtering is usually dominated by the Neel "orange peel" coupling. The orange peel coupling is suppressed dramatically when an oxide layer (OXL) is inserted into the free/pinned FM layers due to smoother surface roughness at the interface. H-int decreases with increasing oxygen exposure dose of the free/pinned FM layers to pure O-2 gas. And it is found that Ruderman-Kittel-Kasuya-Yoshida exchange coupling dominates in OXL spin valves due to smoother surface roughness and enhanced specular electron scattering at the interface between OXL and pinned/free FM layers, which also results in enhancement of magnetoresistance effect. (C) 2001 American Institute of Physics.