Abstract by: Mario I. Trioni

Ab initio Study of Electron Transport in Defective Magnesium Oxide Ultrathin Films in Ag/MgO/Ag Tunnel Junctions

MgO based tunnel junctions received great attention since the theoretical prediction of a 100% magnetoresistance in Fe/MgO/Fe [1,2], a result partially confirmed experimentally that paves the way towards the engineering of miniaturized spintronic devices. Despite a large amount of literature available on this subject, a comprehensive study on the insulating power of MgO ultrathin films inserted between two conducting leads is still missing, especially concerning the presence of defects in the insulating barrier. In our study we proved that even a quite small concentration of point defects in the insulating layer (about 1%) has a large impact on the current flowing between the metallic electrodes.

References:

1 W.H. Butler, X.-G. Zhang, T. C. Schulthess, J. M. Maclaren. Phys. Rev. B 63 (2001) 054416.

2 J. Mathon, A. Umerski. Phys. Rev. B 63 (2001) 220403.