Spin-Guide: A New Source of High Spin-Polarized Current

School of Physics, Georgia Institute of Technology, Atlanta, GA 30332-0430, USA(Dated: January 8, 2003)We propose a “spin-guide” source for generation of electric currents with a high degree of spinpolarization, allowing long-distance transmission of the spin-polarization. In the spin-guide schemeproposed here, a non-magnetic conducting channel is wrapped by a magnetic shell which prefer-entially transmits electrons with a particular spin polarization. It is shown that this method issignificantly more effective then the spin-filter-like scheme where the current flows perpendicular tothe interface between a ferromagnetic metal to a non-magnetic conducting material. Under certainconditions a spin-guide may generate an almost perfectly spin-polarized current, even when themagnetic material used is not fully polarized. The spin-guide is predicted to allow the transportof spin polarization over long distances which may exceed significantly the spin-flip length in thechannel. In addition, it readily permits detection and control of the spin-polarization of the current.The spin-guide may be employed for spin-flow manipulations in semiconductors used in spintronicdevices.