On the use of exchange biased top electrodes in magnetic tunnel junctions

Abstract We have investigated the magnetic behavior and the structural properties of ferromagnetic–antiferromagnetic systems (NiFe–IrMn and Co–IrMn) deposited directly on a thin tantalum buffer layer (bottom configuration) or above a thin Al 2 O 3 tunnel barrier layer (top configuration). In the bottom configuration, the bilayer system exhibits higher magnetic performances than in the top configuration in terms of thermal stability. We have performed a detailed structural study by X-ray diffraction and high-resolution transmission electron microscopy which allow us to establish a clear correlation between the situation of the bilayer with respect to the tunnel barrier, its texture and its magnetic properties.