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MA: Magnetismus

MA 13: Poster:Schichten(1-23),Spinabh.Trsp(24-41),Exch.Bias(42-56),Spindyn.(57-67),Mikromag.(68-76),Partikel(77-90),Spinelektr.(91-97),Elektr.Theo.(98-99),Mikromag+PhasÜ+Aniso.(100-105),Magn.Mat.(106-118),Messmethod.(119-121),Obflm.+Abbverf.(122-123)

MA 13.107: Poster

Dienstag, 9. März 2004, 15:00–19:00, Bereich A

Well-Aligned Co-Filled Carbon Nanotubes: Preparation and Magnetic Properties — •Radinka Kozhuharova¹, Dieter Elefant¹, Andreas Graff^1,2, Albrecht Leonhardt¹, Ingolf Mönch¹, Thomas Mühl¹, Manfred Ritschel¹, Claus M. Schneider^1,3, and Stefka Zotova¹ — ¹Leibniz-Institute of Solid State and Materials Research Dresden, Helmholtzstr. 20, D-01069 Dresden — ²present address: Max Planck Institute of Microstructure Physics, Halle — ³present address: Research Center Jülich GmbH, D-52425 Jülich

Carpet-like flakes (area < 3mm x 3mm; thickness < 500nm) of well-aligned Co-filled multi walled carbon nanotubes were grown by decomposition of cobaltocene. The product was analysed by scanning (FE-SEM, Leo 1530)- and transmission (TEM, Tecnai F30 with GIF200)- electron microscopy. The phase composition and the crystalline structure were determined by X-ray difffraction and selected area electron diffraction. Using alternating gradient magnetometry the ferromagnetic behaviour of the filled nanotubes was investigated. The nanotubes have outer diameter of 50-90nm and diameter of the metal core of 15-30nm. They are discontinuously filled with fcc Co nanowires having a length of up to a few micrometers. Magnetometry measurements show a weak uniaxial magnetic anisotropy with the easy axis along the nanowires. A high coercivity of about 59mT at room temperature is observed, which is significantly higher than in bulk Co.