Berlin 2008 – scientific programme

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MA: Fachverband Magnetismus

MA 32: Postersession II: Spinstruct./Phase Trans. (1-10); Spinelectronics (11-15); Thin Films (16 - 36); Particles/Clusters (37-45); Multiferroics (46-54); Spindynamics/Spin Torque (55 - 76); Post Deadlines (77-79)

MA 32.45: Poster

Friday, February 29, 2008, 11:15–14:00, Poster E

Interactions of magnetic particles in a rotational magnetic field and applications for particle manipulation — •Alexander Weddemann, Ahmed El-Gendy, and Simone Herth — Universität Bielefeld

Magnetic nanoparticles have a growing number of different applications in many different physical, chemical or medical fields. Nevertheless, in many cases several difficulties have to be overcome: Depending on the way of fabrication, the size distribution of the particles is often unknown making it not easy to make proper predictions on the particle behaviour within a physical or biological system. Particle-particle interactions are very strong at short distances leading to agglomerations of the particles. Such clustering of beads can result in a vanishing total magnetic moment, making them useless for certain applications. We introduce a new method to overcome such problems applying time dependent rotational or alternating magnetic fields to particle distributions. The behaviour has been analysed by simulations and in experiments in respect to frequency leading to different characteristic areas of particle behaviour. The influence of the particle diameter on particle movement is discussed as well. Applications of these studies include the avoidance of particle agglomeration, the alignment of elongated macromolecules by loading with magnetic particles, and a new way to determine particle size distributions.