Dresden 2011 – scientific programme

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MA: Fachverband Magnetismus

MA 29: Micro- and Nanostructured Magnetic Materials II

MA 29.4: Talk

Wednesday, March 16, 2011, 11:45–12:00, HSZ 103

Magnetic pinning in self-assembled sub-200nm antidot arrays — •Felix Häring, Ulf Wiedwald, Karsten Küpper, and Paul Ziemann — Universität Ulm, Institut für Festkörperphysik

Self-assembled and isotropically etched Polystyrene (PS) nanoparticles serve as template for the subsequent deposition of magnetic thin films. In this way, films with ordered arrays of antidots are obtained, which can be fine-tuned with respect to their diameters and distances. Both of these parameters are kept within the sub-200nm range. Applying SQUID-magnetometry and magnetotransport measurements, a strong dependence of the magnetic film properties is found on these structural parameters and the film-thickness. For example, an antidot array with a periodicity of 200 nm, antidot diameter of 150 nm within a permalloy film of 20 nm thickness shows a coercive field of 250 Oe, which is an enhancement by a factor of 80 as compared to continuous reference films (3 Oe). This increase is due to domain wall pinning at antidot sites caused by local variations of shape anisotropy. Scanning Transmission X-Ray-Microscopy (STXM) and micromagnetic simulations give further insight into this type of pinning.