Berlin 2005 – wissenschaftliches Programm

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MA: Magnetismus

MA 27: Spindynamik II

MA 27.8: Vortrag

Dienstag, 8. März 2005, 17:00–17:15, TU H1012

Angle dependent switching of spherically shaped nanostructures — •Till C. Ulbrich¹, Ildico L. Guhr¹, Dieter Süss², Tomas Schrefl², Denis Makarov³, Günter Schatz¹, and Manfred Albrecht¹ — ¹University of Konstanz, Department of Physics, 78457 Konstanz, Germany — ²Vienna University of Technology, A-1040 Wien, Austria — ³Taras Shevchenko University, 01033 Kiev, Ukraine

Co/Pd multilayer films provide uniaxial magnetic anisotropy K_u mainly generated by interface anisotropy. The strength and orientation of K_u depends strongly on the individual Co and Pd layer thicknesses. By evaporating of a Co/Pd multilayer film onto a monolayer of self-assembled polystyrene nanoparticles a novel type of magnetic nanostructures is formed on top of the spheres. Due to the spherical shape a spread in anisotropy orientation is present in the magnetic nanostructures. Furthermore, the strength of the anisotropy varies across the nanostructure due to the changing Co layer thickness. These variations have a drastic impact on the switching mechanism which differs remarkably from a Stoner-Wohlfahrt behavior expected for a single domain particle. Here we present first results on the angle dependent switching using nanospheres in the size range of 50 to 310 nm investigated by focused MOKE and MFM. These results were compared to micromagnetic simulations clearly revealing the importance of the local variation of anisotropy induced by the spherical shape of the nanostructures.
This project is funded by the DFG through the SFB 513 A8 and the Emmy-Noether program at the University of Konstanz.