Berlin 2008 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 22: Magnetic Particles / Clusters II

MA 22.10: Vortrag

Mittwoch, 27. Februar 2008, 16:15–16:30, H 1028

The effect of topology, charge and magnetic field on the arrangement of FePt nanomagnets on bacterial S-layers — •Ute Queitsch¹, Anja Blüher², Michael Mertig², Ludwig Schultz¹, and Bernd Rellinghaus¹ — ¹IFW Dresden, P.O. Box 270116 D-01171, Germany — ²MBZ, University of Technology Dresden, Budapesterstr. 27, Dresden, D-01069, Germany

Gas phase preparation has proven to allow for the preparation of L1₀-ordered FePt nanoparticles by in-flight annealing prior to the particle deposition. The regular arrangement of the statistically arriving particles has been shown to be accomplished by depositing onto bacterial surface layers (S-layers) of Bacillus sphaericus NCTC 9602 exhibiting p4 symmetry and a lattice constant of 12.5nm. Aiming at improving the regularity of the particle arrangement we have explored the nature of the interaction between the particles and their affinity sites on the S-layers. Therefore, we have systematically varied both the particle size and charge. Upon adapting the particle size to the size of the template features we observe a pronounced improvement of the regularity. Varying the particle charge resulted only in a minor effect. Hence apparently, the observed affinity originates from topographical effects rather than from electrostatical interactions. In addition, the degree of agglomeration becomes important at high particle densities. Here, applying an in-plane magnetic field during the particle deposition is observed to result in a pronounced decrease of agglomeration and subsequently in an improvement of the regularity at high particle densities.