On the changes at the Fe/MgO interface upon annealing.

Experimental observation of the hybridization of oxygen p states with metal states at the interface in Fe/MgO core/shell self-assembled nanostructures, obtained by vapour-phase deposition, is reported. Synchrotron-based X-ray absorption spectroscopy techniques were used to directly probe the Fe orbital character at the interfacial region. O K edge features suggest the formation of metal-induced states within the band gap of MgO. Thermogravimetric analysis was also used to track interfacial phase changes after different annealing processes. These data demonstrate the relevant role of annealing protocols in controlling the barrier interface, which determine the actual characteristics of spin polarized tunnelling conduction processes. [ABSTRACT FROM AUTHOR]