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MA: Magnetismus
MA 20: Poster: Films(1-36) Transp(37-56) Ex.Bias(57-67) Spindyn(68-80) Micromag(81-95) Particle(96-109) Imag.+Surface(110-113) Spinelectr(114-122) Theory+Micromag(123-131) Spinstr+Aniso(132-142) MagMat(143-156) Meas(157,158) MolMag+Kondo(159-162) Postdead(163-)
MA 20.53: Poster
Tuesday, March 28, 2006, 15:15–19:15, P1
Magnetoresistance behavior of Co nanowires with constrictions — •P. Krzysteczko, M. Brands, and G. Dumpich — Experimentalphysik, Universität Duisburg-Essen (Campus Duisburg), Lotharstraße 1, 47048 Duisburg
We investigate spin transport through a domain wall confined in a nanoconstriction and ballistic spin transport in ferromagnetic crossbar configurations. For this, resistance measurments are performed on polycrystalline cobalt nanowires which are prepared by means of high resolution electron beam lithography (HR-EBL). Constrictions with critical dimensions of the order of 10 nm are prepared at the junction of T-shaped Co nanowires. In order to prevent oxidation some of the Co nanowires are covered in situ with a 2 nm Pt layer or a 10 nm carbon layer. By annealing, the mean grain size of the nanowires has been varied in the range of approximately 7 to 35 nm. The magnetic properties are investigated by magnetic force microscopy (MFM). Due to the shape anisotropy the two sides of the nanocontact respond in different ways to an applied magnetic field. Magnetoresistance measurements were carried out via a four-terminal ac resistance bridge in a 4He bath cryostat at a temperature of T=4.2 K. Magnetic fields up to B=5 T were applied along different in-plane directions. Furthermore, the ballistic transport is investigated by nonlocal resistance measurements.