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MA: Magnetismus

MA 32: Magnetic Particles / Clusters

MA 32.12: Vortrag

Donnerstag, 30. März 2006, 18:00–18:15, HSZ 401

Magnetoviscous behaviour of nanorod ferrofluids — •Dörte Junk, Christian Lang, Andreas Tschöpe, and Rainer Birringer — Universität des Saarlandes, 66123 Saarbrücken, Germany

We prepare shape-anisotropic iron particles in a magnetic-field-assisted forced flux aerosol reactor. On their way downstream the particles are coated with oleic acid and dispersed in a carrier fluid. As in conventional ferrofluids these rod-like particles behave as Brownian particles. Their morphology has been characterized by TEM and ac susceptibility measurements in a dc bias field. We find an average aspect ratio lying between 10 and 15; we will call such a complex fluid nanorod ferrrofluid (nrod FF). The magnetoviscous effect of the nrod FF has been studied using a squeeze flow viscometer (piezoelectric axial vibrator) in the presence of a homogenous magnetic field. The comparison with conventional FF reveals a giant magnetoviscous effect.