Surface and disorder novel effects on interlayer exchange coupling through magnetic tunnel junctions: Ab initio study

3^rd International Conference on Theoretical and Condensed Matter Physics

October 19-21, 2017 New York, USA

Ke Xia, Shizhuo Wang and Youqi Ke

Beijing Normal University, China
Shanghai S T University, China

Scientific Tracks Abstracts: J Material Sci Eng

Abstract :

Based on first principle study, we present the interlayer exchange coupling (IEC) affected by disorders in two types magnetic tunnel junctions (MTJ) structures: Fe/(MgO, Vacuum)/Fe (001) and Vacuum/Fe/(MgO, Vacuum)/Fe (001). Ferromagnetic coupling amplitude exponentially decrease with the barrier thickness, (surface case, disorder etc.)... We also study the interfacial disorder effects on the IEC through Fe/MgO/Fe(001) and Co0.5Fe0.5/MgO/Co0.5Fe0.5 (001) magnetic tunnel junctions (MTJ). As the sign and IEC amplitude across MgO-based MTJ were not consistent in the literatures, which was attributed to the presence of disorder hinted by local impurities model and supercell total energy analysis. Here, we employ the surface Green��?s methods based on TBLMTO to obtain IEC strength, the coherent potential approximation (CPA) method is used to clarify IEC affected by several common types of disorder in MgO based MTJ, such as oxygen vacancy, Boron and Carbon impurities. We found that the character of IEC has strong dependence on the concentration, type and distribution of disorder.

Biography :

Ke Xia has completed his PhD from Nanjing University and Postdoctoral studies from TU Delft and Twente University, Applied Physics department. He is the Head of Department of Physics, BNU China since 2011. He has published more than 80 papers in reputed journals.