Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 26: Exchange Bias
MA 26.5: Vortrag
Donnerstag, 29. März 2007, 16:15–16:30, H10
Orthogonal exchange bias directions in FeMn/NiFe microstructures — •Patrizio Candeloro1, Georg Wolf1, Stefan Trellenkamp2, Christian Dautermann2, Sandra Wolff2, Helmut Schultheiß1, Hans Nembach1,3, and Burkard Hillebrands1 — 1FB Physik and Forschungsschwerpunkt MINAS, TU Kaiserslautern, 67663 Kaiserslautern, Germany — 2Nano+Bio Center, TU Kaiserslautern, 67663 Kaiserslautern, Germany — 3NIST, Boulder, Colorado 80305
The exchange bias effect, arising in ferromagnetic(F)/ antiferromagnetic(AF) bilayers, can be described as an additional unidirectional anisotropy in the F layer. Recently several works have investigated the interplay between unidirectional and uniaxial anisotropies [1,2].
In this work we explore the interplay between exchange bias and twofold shape anisotropy. For this purpose, L-shaped and cross shaped FeMn/NiFe microstructures are fabricated by means of lithographic techniques. Exploiting the shape anisotropy, two orthogonal exchange bias directions are initialized inside the same microstructure via a zero-field cooling technique. MOKE measurements confirm the presence of two biasing directions, parallel to the arms of the structures. Furthermore an unusual angular dependence of the bias field and coercivity is observed, due to the interplay between the twofold unidirectional and shape anisotropies.
Financial support by the EU-RTN NEXBIAS is acknowledged.
[1] S. H. Chung et al., Phys. Rev. B 71 (2005) 214430
[2] S. Brück et al., Adv. Mater. 17 (2005) 2978