Atomic-scale characterization of a Co/AlOx/Co magnetic tunnel junction by scanning transmission electron microscopy

Analytical electron microscopy has been employed to characterize the localized physical and electronic structure of a Co/AlOx/Co magnetic tunnel junction. The tunnel barrier is amorphous alumina with an extensive conduction band tail due to disorder. Both barrier edges are Al terminated and an Al-rich layer exists at the bottom Co/AlOx interface. sp-d hybridization between interfacial Co and Al atoms is observed and it is likely that the interfacial Al is metallic. All of these features are expected to be important to the magnetoresistance behavior of the junction. (C) 2001 American Institute of Physics.