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M: Metallphysik

M 28: Nanoskalige Materialien II

M 28.1: Fachvortrag

Donnerstag, 29. März 2001, 11:45–12:00, S5.3

Magnetic Nanocarpets: A new self-organization phenomenon of iron nanoparticles — •Helmut Wolf and Rainer Birringer — Universität des Saarlandes, FR 7.3 Technische Physik, 66123 Saarbrücken

Collecting magnetic nanoparticles from a continous aerosol flow in a homogeneous magnetic field, the particles arrange to chain-like threads on the substrate, growing in the direction of the applied magnetic field. During chain growth one observes a hierarchy of unexpected self-organization phenomena that orignate from structural instabilities. At a chainlength of about 100 nm, the chains are rearranged to bundles with a diameter of 200–500 nm, each consisting of a polymer-like network of 20–200 nanoparticle chains. These bundles repeat the carpet formation at a larger scale. At a length of about 40 µm this ”supercarpet” develops new types of regularly evolving density patterns with a typical structure size of 100 µm. The formation of locally hexagonal lattices of flower-like pores in the homogeneous supercarpet is observed as well as more complicated patterns.