Regensburg 2013 – scientific programme
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MA: Fachverband Magnetismus
MA 50: Poster II
MA 50.26: Poster
Friday, March 15, 2013, 10:30–13:30, Poster D
Roughness investigations of a CoFeB-MgO nanowire — •Tim Zacke1, Tomek Schulz1, Su Jung Noh1, Benjamin Krüger1, Capucine Burrowes1, Dafiné Ravelosona2, and Matthias Kläui2 — 1Institut of physics, University of Mainz, Mainz, 55128, Germany — 2Institut d'Elecronique Fondamentale, Univerité Paris Sud, Orsay, 91405, France
We have investigated the impact of roughness on the domain wall dynamics in a nanowire, consisting of the multilayer stack CoFeB/MgO, which exhibits a high magnetic perpendicular anisotropy. These investigations were carried out by numerical simulations using the object oriented micro magnetic framework (OOMMF) based on the Landau-Lifshitz-Gilbert (LLG) - equation and the micromagnetic model. By varying the key roughness parameters (correlation length and amplitude), we determine the dependence on the pinning strength (wall propagation field) on these parameters and correlate the wall width with these. To compare with experimental results, we nucleate a DW in a CoFeB/MgO by an Oersted field generated by a gold wire on top of the magnetic wire. We then measure the wall propagation field at variable temperature down to 4K. This allows us to determine by comparison between experimental and theoretical results the effective magnetic roughness of the wire. Comparison to high resolution microscopy images allows us to ascertain to what extent the visible roughness and the magnetic roughness correlate yielding insights on the homogeneity of the magnetic properties at the wire edge.