Regensburg 2010 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
MA: Fachverband Magnetismus
MA 28: Spin-dependent Transport Phenomena
MA 28.7: Vortrag
Donnerstag, 25. März 2010, 16:45–17:00, H3
Magnetism and spin transport in spin filter/silicon heterostructures — •Martina Müller1, Marc J. van Veenhuizen2, Jagadeesh S. Moodera2, and Claus M. Schneider1 — 1Institut für Festkörperforschung, Forschungszentrum Jülich — 2Francis Bitter Magnet Laboratory, MIT, USA
Controlling spin transport in ferromagnet(FM)/semiconductors(SC) systems is a key objective in the development of semiconductor spintronics. Recently, spin injection and -detection into silicon (Si) has been realized using FM/oxide tunnel contacts. Here, we present an alternative route to engineer functional spin tunnel contacts, which are based on magnetic insulator/Si heterostructures.
We fabricated EuS/Si and Co/EuS/Si embedded tunnel contacts on n-doped Si substrates. Ferromagnetic EuS tunnel barriers were grown by means of MBE, with thicknesses between d=2 to 6 nm. The transport experiments showed a characteristic metal-to-insulator transition of EuS at T<20 K, which clearly confirms a spin filter effect being in effect. I(V) measurements revealed a highly non-linear behavior indicative for tunnel transport. However, no totally symmetric I(V) curves were found under forward/reverse bias, which is due to an additional Schottky barrier present at the EuS/n-Si interface. MR measurements of Co/EuS/Si contacts yielded MR values up to 10% combined with a pronounced bias voltage dependence. This unique feature is due to superimposing spin tunneling pathes [1] and principally should allow the electrical injection of spins into silicon at elevated bias voltages.
[1] G.-X. Miao, M. Müller, J. S. Moodera, PRL 102, 076601 (2009)