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HL: Fachverband Halbleiterphysik

HL 101: Transport: Nanoelectronics II - Spintronics and Magnetotransport (jointly with TT, MA)

HL 101.8: Talk

Friday, March 30, 2012, 11:30–11:45, BH 243

Gate dependent TMR-effect in a SWCNT-based spin valve device with exchange biased ferromagnetic contacts — Andreas Prüfling, •Daniel Steininger, Maurice Ziola, Matthias Sperl, Andreas K. Hüttel, and Christoph Strunk — Universität Regensburg, Germany

We report on magneto-transport measurements on a single wall carbon nanotube based spin valve device with Permalloy (Ni₈₁Fe₁₉) and Ni₈₁Fe₁₉/Fe₅₀Mn₅₀ bilayer contacts. Sputtered thin films and EBL-patterned strip-arrays of these materials were characterized by means of vibrating sample- and SQUID magnetometry and optimized by varying both layer thickness ratios, and material grain size via the sputtering power. Utilizing the magnetic exchange bias effect in these ferromagnet/anti-ferromagnet bilayer systems, the difference in cooercive fields of our contacts is sufficently large to achieve controllable independent switching of two contacts by an external magnetic field. Magneto-transport measurements performed in the Coulomb blockade- and Kondo regime of a SWCNT quantum dot device show systematic gate dependence of the tunneling magnetoresistance (TMR) when the gate voltage is scanned through several Coulomb diamonds.