Dresden 2011 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 63: Poster II (Surface Magnetism/ Magnetic Imaging/ Topological Insulators/ Spin Structures and Magnetic Phase Transitions/ Graphene/ Magnetic Thin Films/ Magnetic Semiconductors/ Magnetic Half-metals and Oxides/ Spin-dependent Transport/ Spin Excitations and Spin Torque/ Spin Injection and Spin Currents in Heterostructures/ Spintronics/ Magnetic Storage and Applications)

MA 63.74: Poster

Freitag, 18. März 2011, 11:00–14:00, P2

Spin filter contacts to Silicon using magnetic insulators: EuS/Si(001) — •Martina Müller, Reinert Schreiber, and Claus M Schneider — Forschungszentrum Jülich, Institut für Festkörperforschung (IFF-9), 52425 Jülich, Germany

Efficient spin filtering through magnetic insulators has been envisioned for sensitive spin injection and -detection in semiconductors. In our work, focus is put on establishing spin filter functionality of ultrathin films of the magnetic insulator EuS grown directly on silicon. We investigate EuS tunnel barriers combined with nonmagnetic NM and ferromagnetic FM electrodes in the light of their possible application as dedicated spin tunnel contacts to silicon. Our study of the electrical transport across Si(001)/EuS/NM and Si(001)/EuS/FM tunnel contacts, which is supported by a detailed magnetic characterization of the samples, evidences the influence of the work function of the NM and FM electrodes on the bias dependent tunnel current. We assigned the temperature-dependent electrical transport mechanisms in our systems and addressed the question, how a Schottky barrier formation can be reduced in order to enhance the EuS spin filter effect. We finally could show, that tunnel magnetoresistance effects, though still moderate, arise in both Si(001)/EuS/FM spin valves and estimated a EuS spin filter efficiency of about 20%, which coincides very well for both systems. In general, our experimental findings point encouraging towards the successful implementation of spin filter tunnel contacts into silicon heterostructures.