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Physics Colloquium, November 20, 2001Fast switching of nano- and mesoscopic elements: A micromagnetic studyJosef FidlerVienna University of Technology Institute of Applied and Technical PhysicsSwitching of small particles, thin film elements and nano-wires becomes increasingly important in magnetic storage and magneto electronic devices. The magnetization reversal processes are studied using a 3D hybrid finite element/boundary element micromagnetic model. Transient magnetization states during switching are investigated numerically in thin NiFe and Co nano-elements of various shapes. Switching dynamics are calculated for different external field profiles and frequencies. The numerical solution of Brown's equations can be effectively performed using finite-element and related methods that easily handle complex microstructures and take into account the long-range magnetostatic interactions and short-range exchange coupling between the grains. Dynamic finite-element simulations successfully predict the influence of microstructural features like grain size, particle shape, intergranular phases, and surface irregularities on the magnetic properties. Theoretical limits for remanence, coercive field, switching behavior at a short time scale, and other properties have successfully been calculated. For more information see Dr. Fidler's page 3.30 p.m., Smith Laboratory, Room 1005Refreshments served in Smith 1094 at 3:00 p.m. |
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