Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 10: Spinelectronics/Spininjection in Heterostructures
MA 10.1: Vortrag
Montag, 26. März 2007, 15:15–15:30, H23
Remanent spin injection and spin density distribution in a spin FET structure — •Philipp Kotissek1, Matthieu Bailleul2, Matthias Sperl1, Alexander Spitzer1, Dieter Schuh1, Werner Wegscheider1, Christian Back1, and Günther Bayreuther1 — 1Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg, Germany — 2IPCMS/GEMME, 23 rue du Loess, BP 43, 67034 Strasbourg, France
The spin field-effect transistor first proposed by Datta and Das is considered to be the paradigm of spintronic devices. Spin injection and detection are the main requirements for the implementation of such a device. Electric spin injection has recently been achieved by inserting a Schottky barrier or a tunnel barrier between a ferromagnetic metal source contact and the semiconductor. The detection techniques used up to now require large magnetic fields, or they only measure a transient component of the polarization. Here we introduce a novel optical spin detection method from a cleaved edge of the semiconductor wafer which allows us to visualize directly electrical spin injection into GaAs from a magnetically soft FeCo film at remanence. The spin polarization can be reversed by a small magnetic field. Moreover, we could quantitatively determine the dependence of the spin polarization of the current on the injection energy. The local spin density distribution in the semiconducting channel including depth profiles for different geometries can be directly accessed. This method will be particularly useful for the future development of semiconductor-based spintronic devices.