Berlin 2012 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 13: Transport: Poster Session

TT 13.12: Poster

Monday, March 26, 2012, 15:00–19:00, Poster B

Magnetoresistance measurements on carbon nanotubes with CoPd contacts — •Dominik Metten¹, Caitlin Morgan¹, Claus M. Schneider^1,2, and Carola Meyer^1,2 — ¹Forschungszentrum Jülich, Peter Grünberg Institut (PGI-6) and JARA Jülich Aachen Research Alliance, 52425 Jülich, Germany — ²Fachbereich Physik, Universität Duisburg-Essen, 47048 Duisburg, Germany

Carbon nanotubes (CNTs) are expected to show a long spin relaxation length because they exhibit small hyperfine coupling and have small spin-orbit interactions. These properties, along with ballistic electron transport, lead to a high potential for applications in the field of spintronics.

We study spin injection in CNT-based devices using Co₅₀Pd₅₀ as contacts. Palladium is known to have low contact resistivity to CNTs and is easily spin-polarized by cobalt. Shape anisotropy is used to ensure in-plane magnetization and to prevent formation of multiple domains in the contacts.

Here we present a magnetic characterization of the contacts including SQUID- and MFM-measurements. First magnetoresistance (MR) measurements show an MR effect of 5% with clear switching behavior. Our devices can be tuned using a backgate. Gate dependent measurements reveal different regimes for the MR effect. Since a potential barrier forms at the interface between the contacts and the CNT, tunneling MR is the expected mechanism.