2004/09/07 by X.-G. Zhang, X. -G. Zhang, W. H. Butler · 4 citations
Physics and Astronomy · #Magnetic properties of thin films #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.70.172407
published as Phys. Rev. B 70, 172407 (2004) · 8 figure files in eps format
arxiv created 2004/09/07 · openalex publication_date 2004/11/17 · arxiv updated 2009/12/01 · openalex created_date 2017/03/16 · openalex updated_date 2026/07/28
By use of first-principles electronic structure calculations, we predict that the magnetoresistance of the bcc Co(100)∕MgO(100)∕bccCo(100) and FeCo(100)∕MgO(100)∕FeCo(100) tunneling junctions can be several times larger than the very large magnetoresistance predicted for the Fe(100)∕MgO(100)∕Fe(100) system. The origin of this large magnetoresistance can be understood by considering the electrons at the Fermi energy traveling perpendicular to the interfaces. For the minority spins there is no state with \ensuremathΔ1 symmetry whereas for the majority spins there is only a \ensuremathΔ1 state. The \ensuremathΔ1 state decays much more slowly than the other states within the MgO barrier. In the absence of scattering which breaks the conservation of momentum parallel to the interfaces, the electrons traveling perpendicular to the interfaces undergo total reflection if the moments of the electrodes are antiparallel. These arguments apply equally well to systems with other well ordered tunnel barriers and for which the most slowly decaying complex energy band in the barrier has \ensuremathΔ1 symmetry. Examples include systems with (100) layers constructed from Fe, bcc Co, or bcc FeCo electrodes and Ge, GaAs, or ZnSe barriers.