Spin-polarized Andreev reflection tunneling through a precessing magnetic spinYao-Ming Shi1, Shi-Ping Zhou1, Xiu-Feng Cao1, Hao Huang1 and Hao Chen2
1 Department of Physics, Shanghai University - Shanghai 200444, PRC
2 Department of Physics, Fudan University - Shanghai 200433, PRC
received 13 September 2005; accepted in final form 16 January 2006
published online 10 February 2006
We study theoretically the spin-polarized Andreev reflection tunneling through a local precessing magnetic spin weakly coupled to a ferromagnet and to a superconductor. The linear Andreev reflection conductance is obtained at zero temperature by using a nonequilibrium Green function approach. It shows that the spin-exchange interaction on the local spin-site can result in two spin-coherent states, from which the Andreev reflection conductance resonance with either a double peak or a single peak is developed. We find that the spin-orbit interaction in the barrier between the local spin-site and the ferromagnet-electrode leads only to a conductance oscillation with base frequency twice the Larmor frequency, , and a variable amplitude with equilibrium chemical potential and spin-flip tunneling coupling.
73.63.-b - Electronic transport in nanoscale materials and structure.
85.75.-d - Magnetoelectronics; spintronics: devices exploiting spin-polarized transport or integrated magnetic fields.
73.40.Gk - Tunneling.
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