Daniel Lengemann

Publications of Daniel Lengemann

• Asymmetric magnetization reversal of stripe-patterned exchange bias layer systems for controlled magnetic particle transport.

  Authors: Arno Ehresmann, Daniel Lengemann, Tanja Weis, Alla Albrecht, Jannick Langfahl-Klabes, Florian Göllner, Dieter Engel

  Advanced materials (Deerfield Beach, Fla.). 11/2011; 23(46):5568-73.

  Domain wall movement assisted transport of particles: exchange-biased samples with designed stripe-domains show strong stray fields and an asymmetric magnetization reversal. Using theseDomain wall movement assisted transport of particles: exchange-biased samples with designed stripe-domains show strong stray fields and an asymmetric magnetization reversal. Using these characteristics superparamagnetic particles can be trapped and transported directly on the sample over large-scale areas. High particle velocities, small external fields, and automatically reduced particle clustering allow broad applicability of this transport method.

• Colloidal domain lithography for regularly arranged artificial magnetic out-of-plane monodomains in Au/Co/Au layers.

  Authors: Piotr Kuświk, Arno Ehresmann, Maria Tekielak, Bogdan Szymański, Iosif Sveklo, Piotr Mazalski, Dieter Engel, Jan Kisielewski, Daniel Lengemann, Maciej Urbaniak, Christoph Schmidt, Andrzej Maziewski, Feliks Stobiecki

  Nanotechnology. 03/2011; 22(9):095302.

  Regularly arranged magnetic out-of-plane patterns in continuous and flat films are promising for applications in data storage technology (bit patterned media) or transport of individual magneticRegularly arranged magnetic out-of-plane patterns in continuous and flat films are promising for applications in data storage technology (bit patterned media) or transport of individual magnetic particles. Whereas topographic magnetic structures are fabricated by standard lithographical techniques, the fabrication of regularly arranged artificial domains in topographically flat films is difficult, since the free energy minimization determines the existence, shape, and regularity of domains. Here we show that keV He(+) ion bombardment of Au/Co/Au layer systems through a colloidal mask of hexagonally arranged spherical polystyrene beads enables magnetic patterning of regularly arranged cylindrical magnetic monodomains with out-of-plane magnetization embedded in a ferromagnetic matrix with easy-plane anisotropy. This colloidal domain lithography creates artificial domains via periodic lateral anisotropy variations induced by periodic defect density modulations. Magnetization reversal of the layer system observed by magnetic force microscopy shows individual disc switching indicating monodomain states.