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TT: Fachverband Tiefe Temperaturen
TT 49: Spintronics (organized by MA)
TT 49.8: Vortrag
Dienstag, 1. April 2014, 15:30–15:45, HSZ 401
Barrier dependent tunneling magnetoresistance in carbon nanotubes — •Carola Meyer1,2, Cate Morgan1,2, Dominik Metten3, Sebastian Heedt1,2, Thomas Schäpers1,2, and Claus M. Schneider1,2 — 1Peter Grünberg Institut, Forschungszentrum Jülich, 52425 Jülich, Germany — 2JARA - Fundamentals of Future Information Technologies — 3Institut de Physique et Chimie des Matériaux de Strasbourg and NIE, UMR 7504, Université de Strasbourg and CNRS, France
Carbon nanotubes (CNTs) are a material of interest in spintronics, because in addition to exhibiting ballistic transport, the low atomic number and low abundance of 13C nuclei in CNTs is expected to lead to low spin orbit coupling and hyperfine interaction indicating a long spin relaxation time. However, the size of the magnetoresistance (MR) observed depends strongly on the current regime and on the type of CNT device measured. In the single-electron-tunneling regime, typically only a few percent MR can be reached. MR in multiwalled CNTs with a large diameter has shown to be as large as 60% for contacts with high polarization [1].
We present a way to compare the MR of different devices from single-wall and multiwalled CNTs with respect to the current regime. Temperature dependent data confirm tunneling MR as the main effect. The size of the MR measured depends on the strength of the tunnel barrier and follows the Slonczewski model. Finally, the presence of the Hanle effect proves successful spin injection.
[1] L. E. Hueso et al., Nature 445, 410 (07)