title: Electron holography study on the microstructure of magnetic tunnelling junctions.
abstract: Electron holography was applied to study the microstructure evolution of magnetic tunnelling junctions (MTJs) CoFe/AlO(x)/Co annealed at different temperatures. A mean inner potential barrier was observed in the as-deposited MTJ sample, while it was changed to a potential well after a 200 degrees C or a 400 degrees C annealing. It is suggested that the oxygen atoms were redistributed during the annealing, which left metallic atoms acting as acceptors to confine the electrons, leading to the decrease of the potential of the AlO(x) barrier layer. The results suggest that the electron holography may be a useful tool for the study of the microstructure of amorphous materials.
authors.affiliation: Beijing Laboratory of Electron Microscopy, Institute of Physics and Center for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Q Y
authors.initials: QY
authors.lastname: Xu
authors.forename: Y G
authors.initials: YG
authors.lastname: Wang
authors.forename: B
authors.initials: B
authors.lastname: You
authors.forename: J
authors.initials: J
authors.lastname: Du
authors.forename: A
authors.initials: A
authors.lastname: Hu
authors.forename: Z
authors.initials: Z
authors.lastname: Zhang