Dresden 2006 – wissenschaftliches Programm
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MM: Metall- und Materialphysik
MM 30: Symposium Nano Wires (SYNW)
MM 30.7: Vortrag
Donnerstag, 30. März 2006, 12:30–12:45, IFW D
Electrical Properties of Self-Assembled Iron Nano Chains — •Hanna Onneken1, Tim Hülser1,2, Hartmut Wiggers2, and Axel Lorke1 — 1Institute of physics, University Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany — 2Institute of combustion and gas dynamics, University Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany
We report on the electrical properties of self-assembled iron nano-chains. Morphological, structural and magnetic investigations confirm the existence of chains up to 300µm lengths, consisting of iron nano-particles with diameter of about 35nm. A surrounding iron oxide shell on the particles can be explained by a self-limited oxidation process in ambient atmosphere.
Single chains can be deposited on substrates for electrical characterization or consequently collected in a particle precipitator for subsequent processing. Impedance Spectroscopy (IS) on single chains reveals two contributions to the overall impedance. The first contribution, an ohmic resistance is originated by the iron core of each particle. The second results from the intergranular contact between adjacent particles with a capacitance between the conducting iron cores, surrounded by the shell. From the core contribution a specific resistance of 4.4x10−8 Ωm has been calculated; this value is of the same order as that of bulk iron. Agglomerated chains from the precipitator can be separated in ultrasonic baths using polar and nonpolar solvents and consequently contacted via electron beam lithography for IS analysis.