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MA: Fachverband Magnetismus

MA 37: Spin Dependent Transport Phenomena

MA 37.5: Vortrag

Donnerstag, 26. März 2009, 16:15–16:30, HSZ 403

Hot electron transport in thin bcc FeCo spin valves - Room temperature Magnetocurrent exceeding 1200% — Christoph Kefes, •Emanuel Heindl, Johann Vancea, and Christian Back — Department of Physics, University of Regensburg, 93040 Regensburg, Germany

We use the tip of a scanning tunneling microscope to create a nonequilibrium unipolar electron distribution in a metal layer and measure the subsequent perpendicular ballistic hot electron transport through thin single crystalline metallic spin valves by employing ballistic electron emission microscopy (BEEM). By variation of the thickness of one of the ferromagnetic layers we can determine the spin dependent attenuation lengths which reflect the bulk hot electron transport along the [100]-axis of the bcc FeCo-layers. While the minority spin attenuation length is found to be energy independent and about 0.8 nm, the majority spin attenuation length is about 6 times larger within the measured energy interval of 1.3 up to 2 eV above the Fermi level. Consequently, a magnetocurrent effect exceeding 1200 % accompanied by a monotonic bias voltage behavior is observed at room temperature.