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MA: Fachverband Magnetismus

MA 5: Micro- and Nanostructured Magnetic Materials I

MA 5.2: Vortrag

Montag, 22. März 2010, 11:15–11:30, H23

Magnetic Reversal in Iron Thin Films Interspersed with Non-Magnetic Pinning Sites — •Stefan Nau, Ulf Wiedwald, Stefan Wiedemann, Alfred Plettl, and Paul Ziemann — Institut für Festkörperphysik, Universität Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany

Magnetic switching of continuous iron thin films is tailored by structuring a periodic array of nonmagnetic holes acting as pinning centers for domain walls. Contrary to common lithographically prepared antidots, nanostructures are prepared by deposition of densely packed monolayers of polystyrene (PS) spheres on silicon and silicon nitride substrates. Isotropic plasma etching leads to adjustable PS diameters between 20% and 80% of the initial value while conserving the particle spacing. The influence on the magnetic reversal process is studied as a function of diameter and distance of the PS spheres. Iron films are deposited by pulsed laser deposition. Antidot arrays of 100 nm period lead to up to 15 times increased in-plane coercive fields at 300 K, depending on dot diameters and film thicknesses. The magnetic reversal is imaged by scanning transmission x-ray microscopy accompanied by micromagnetic simulations in order to understand domain nucleation and propagation in varying external fields.