Berlin 2008 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 18: Poster I : Bio Magn. (1-2); Mag.Imgaging (3-9); Magn. Semiconductors (10-16); Half Metals & Oxides (17-20); Coupl.Phenomena (21-27); Magn. Mat. (28-41); Micro & Nanostr. Magn. Materials (42-61); Micro Magn. (62-64); Surface Magnetism (65-70); Transport Phenomena (71-85)
MA 18.23: Poster
Dienstag, 26. Februar 2008, 15:15–18:30, Poster E
Local magnetization study of exchange bias in patterned Co/CoO dots — •Ulrike Wolff1, Sarah Suck2, Dominic Givord2, Jeffrey McCord1, Ludwig Schultz1, and Volker Neu1 — 1IFW Dresden, P.O. Box 270116, D-01171 Dresden, Germany — 2Institut Néel, CNRS-UJF, 25 avenue des Martyrs, F-38042 Grenoble, Cedex 9, France
It is well known that exchange-bias (EB) originates from symmetry breaking at the interface between a ferromagnet (FM) and an antiferromagnet (AFM). However, due to the presence of complex disordered structural and magnetic configurations at the FM/AFM interfaces, a clear description of this phenomenon is still missing. The role of structural and magnetic defects is expected to be considerably reduced at the nanosize when the single crystalline and single domain state is entered [1]. Therefore, the present work focuses on the study of the local magnetization process in arrays of small (120 x 360 nm2) Co/CoO dots by magnetic force microscopy at low temperatures (50 K) and in an applied in-plane field. The dots behave as magnetic dipoles where the magnetization reversal mainly occurs in a single switching event explained by a coherent rotation process modified by the exchange bias. Nevertheless, in some dots multidomain formation is observed upon reversal. This behaviour is compared with global magnetization measurements and with additional Kerr microscopy experiments, which probe the magnetization reversal on an intermediate mesoscopic scale.
[1] J. Nogués, J. Sort, V. Langlais, V. Skumryev, S. Surinach, J.S. Munoz, M.D. Baro, Phys. Rep. 422 (2005) 65