Dresden 2003 – wissenschaftliches Programm

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MA: Magnetismus

MA 6: Magnetische Partikel / Cluster

MA 6.1: Vortrag

Montag, 24. März 2003, 15:15–15:30, HSZ/04

AFM / MFM studies on the behavior of superparamagnetic clusters in external magnetic fields — •Jiandong Wei, Martin Oberringer, Astrid Mueller, Yunhui Xu, Adam Janoschka, and Uwes Hartmann — Institute of Experimental Physics,University of Saarbruecken,66401 Saarbruecken, Germany

Behavioral evidences and histological research have indicated that magnetic interactions between the superparamagnetic (SP) clusters inside the pigeon’s tissues and the geomagnetic field may provide an important clue for the bird to navigate during a long-distance travel. This SP clusters are about 1-2 microns in diameter and the fine magnetite crystals inside have an average dimension of several nanometers. In order to model the function of the magnetic detection system, model experiments with ferrofluids in external magnetic fields have been performed by AFM /MFM at a scale down to a few nanometers. Both the natural SP clusters and ferrofluid aggregates show a common magnetic behavior in external magnetic fields. Especially, the deformation and rearrangement of SP aggregates as a function of the external magnetic field have been studied. The latter is the basic phenomena in the theory of the magnetoreceptor based on SP magnetite crystals. Thus, AFM /MFM provide promising methods to understand the magnetic detection mechanism of pigeons in detail