Regensburg 2010 – scientific programme
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MA: Fachverband Magnetismus
MA 24: Spinelectronics / Spin Injection in Heterostructures
MA 24.7: Talk
Thursday, March 25, 2010, 11:45–12:00, H22
In-situ fabrication of lateral organic spin-valve structures with sub-100nm channel-length — •Matthias Grünewald1,3, Frank Würthner2, Georg Schmidt1,3, and Laurens W. Molenkamp1 — 1Experimentelle Physik 3, Universität Würzburg, Am Hubland, 97074 Würzburg — 2Organische Chemie 2, Universität Würzburg, Am Hubland, 97074 Würzburg — 3Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle
Many spin-valves (SVs) based on an organic semiconductor (OSC) layer sandwiched between two ferromagnetic electrodes have been demonstrated recently. It is, however, still unclear whether the observed effect is based on GMR or TMR because intermixing during the metal deposition on top of the OSC layer can reduce the effective layer thickness. Lateral transport structures using an OSC layer deposited in the gap between two electrodes avoid this possible side effect, but may suffer from interface contamination or oxidation during the lithography process.
Here we report the fabrication of lateral SV structures using a combination of optical lithography and shadow evaporation. The process allows for the in-situ deposition of two ferromagnetic contacts with different coercive fields, separated by a gap of about 80 nm, and covered by a layer of the n-type OSC perylene-diimide. Magnetic and electrical properties are investigated, and gate dependent measurements are performed showing clear gate action. Magnetotransport studies at room temperature show SV action with a magnetoresistance ratio of up to 50% and I/V characteristics indicate lateral tunneling.