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 locali zed physical and electronic structure of a Co/AlOx/Co magnetic tunnel junct ion. The tunnel barrier is amorphous alumina with an extensive conduction b and tail due to disorder. Both barrier edges are Al terminated and an Al-ri ch 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 interfac ial Al is metallic. All of these features are expected to be important to t he magnetoresistance behavior of the junction. (C) 2001 American Institute of Physics.