Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 23: Micro- and Nanostructured Magnetic Materials I
MA 23.1: Vortrag
Donnerstag, 29. März 2007, 10:15–10:30, H22
Sub 20nm structures with perpendicular magnetization — •Holger Stillrich1, Sabine Pütter1, Andreas Frömsdorf2, and Hans Peter Oepen1 — 1Institut für Angewandte Physik, Universität Hamburg, Jungiusstr. 11, 20355 Hamburg, Germany — 2Institut für Physikalische Chemie, Universität Hamburg, Grindelallee 117, 20146 Hamburg, Germany
Magnetic nanostructures with perpendicular magnetic anisotropy are fabricated using SiO2 nanoparticles. SiO2 filled diblock copolymer micelles are deposited as a single layer on a Co/Pt multilayer film with perpendicular easy axis of magnetization. The polymer shell is removed in an oxygen plasma which yields a SiO2 particle array that is used as mask for ion milling. Two kinds of diblock copolymers with different polymer length are used. The mean particle diameter is 12 and 20nm and the mean particle distance is 30 and 80nm, respectively, which was determined via AFM and SEM investigations. After sputtering a replica in the Co/Pt film is produced with slightly reduced dot size.
The magnetic properties of both films and magnetic dot arrays are investigated via the magneto-optical Kerr effect.
We find that the 20nm dots are ferromagnetic at room temperature and the perpendicular easy axis of the Co/Pt multilayer is preserved. The 12nm dots are superparamagnetic at room temperature. The influence of ion energy, number of Co/Pt-bilayers and size distribution of magnetic dots on the average magnetic properties is discussed.
Funding by the DFG via SFB 508 is gratefully acknowledged.