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MA: Fachverband Magnetismus
MA 40: Poster II: Bio- and Molecular Magnetism (1-9); Magnetic Coupling Phenomena/Exchange Bias (10-15); Magnetic Particlicles and Clusters (16-29); Micro and Nanostructured Magnetic Materials (30-51); Multiferroics (52-64); Spin Injection in Heterostructures (65-67); Spin-Dyn./Spin-Torque (68-93); Spindependent Transport (94-108)
MA 40.51: Poster
Friday, March 27, 2009, 11:00–14:00, P1A
Synthesis of novel tubular shaped nanoparticles for application as a ferrofluid — •Robert Zierold1, Julien Bachmann1, Zhenyu Wu2, Carl Krill2, and Kornelius Nielsch1 — 1Institute of Applied Physics and Microstructure Research Center Hamburg, University of Hamburg — 2Institute of Micro- and Nanomaterials, University of Ulm
A novel, fully tunable preparation of short (aspect ratio <10) ferromagnetic nanotubes is presented. Combining porous alumina as a template with Atomic Layer Deposition (ALD) offers the possibility of producing magnetic nanotubes [1]. By reducing the anodization time of aluminum and implementing multilayer ALD of silica and iron oxide, it is possible to control all system parameters (e.g. length, wall thickness, magnetic moment) of the tubular nanoparticles. By releasing the embedded tubes a ferrofluid-like suspension is formed. A novel synthesis strategy has been implemented for recycling the supporting aluminum substrate. The fluid viscosity is studied as a function of the applied magnetic field and the shear rate with a piezo-membrane axial vibrator. Compared to spherical nanoparticles of conventional ferrofluids, the tubular structure-based solution is expected to suppress shear-thinning effects [2] at higher shear rates. [1] J. Bachmann et al., J. Am. Chem. Soc., 129, 9554 (2007). [2] S. Odenbach et al., J. Magnet. Magnet. Mater., 183, 188 (1998). The authors thank the DPG (SPP1165) for financial support.