Regensburg 2013 – scientific programme
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DF: Fachverband Dielektrische Festkörper
DF 22: Poster II
DF 22.37: Poster
Friday, March 15, 2013, 10:30–13:30, Poster D
Magnetization Reversal Mechanisms in Co-Antidot Arrays — Manuel Langer1, •Rantej Bali1, Ewa Kowalska1, Andreas Neudert1, Kilian Lenz1, Kay Potzger1, Mikhail Kostylev2, Adekunle Adeyeye3, Jürgen Fassbender1, and Jürgen Lindner1 — 1Helmholtz-Zentrum Dresden-Rossendorf e.V., 01328 Dresden, Germany — 2School of Physics, University of Western Australia, Crawley 6009, Australia — 3Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore
Co-antidots with holes arranged in the form of a square lattice, with lattice parameter of 415 nm and hole diameter d = 145 to 255 nm were fabricated using DUV photolithography. For arrays with film thickness of 50 nm, the angular dependence of the saturation field (Hs) shows presence of four-fold anisotropy with the hard axes along the <01> directions and easy axes was along the diagonal <11> directions. Spikes in the Hs were measured along the intermediate <12> directions. Kerr microscopy suggests that the reversal mechanism along the <01> is domain-wall (DW) depinning followed by propagation within the continuous channels along the <01>, whereas along the <11> the mechanism tends towards nucleation and growth. We postulate that the Hs-spikes occur because DW-propagation requires domino-like spin-reorientations through the continuous channels, whereas nucleation can only occur when a coherent region is formed with the spins oriented along the applied field. The frustration caused by the two possible spin-reorientation paths results in the larger Hs. We attempt to model these mechanisms using OOMMF and investigate the influence of varying d.