Spin-filtering effect in a two-dimensional electron gas under a local fringe field

We fabricated a spin‐filtering device which consists of InAs based two‐dimensional electron gas and two ferromagnetic pads. A fringe field at the edge of a ferromagnetic pad was used to induce spin polarization of the moving electrons in a two‐dimensional electron gas. The direction of the fringe field was determined by the magnetization of the ferromagnetic pad, which was switched by using the external magnetic field. A current of which spins were aligned by one fringe field (polarizer) was filtered by the other fringe field (analyzer). The resistance of the device was in either a high state or a low state depending on the alignment of the fringe fields. The spin‐filtering effect diminishes rapidly as the thermal energy exceeds the Zeeman splitting. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)