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MA: Fachverband Magnetismus

MA 19: Poster I (Bio- and Molecular Magnetism/ Magnetic Particles and Clusters/ Micro- and Nanostructured Magnetic Materials/ Magnetic Materials/ Multiferroics/ Magnetic Shape Memory Alloys/ Electron Theory of Magntism/ Spincaloric Transport/ Magnetic Coupling and Exchange Bias/ Magnetization Dynamics/ Micromagnetism and Computational Magnetics)

MA 19.17: Poster

Tuesday, March 15, 2011, 10:45–13:00, P2

Competition of dipolar interactions and lateral exchange spring effect in NiFe elements — •Norbert Martin¹, Ingolf Mönch², Rudolf Schäfer², Ludwig Schultz², Jürgen Fassbender¹, and Jeffrey McCord¹ — ¹Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden — ²Leibniz Institut für Festkörper- und Werkstoffforschung Dresden, Helmholtzstr. 20, 01069 Dresden

Conventional exchange spring systems consist of directly exchange coupled hard and soft magnetic layers. In the presented work, lateral exchange spring structures were prepared by structured ion implantation on patterned samples to investigate the interplay between structuring and additional dipolar fields. The collective magnetization reversal of hard and soft phase is attributed to strong dipolar fields at the element edges that cause a hysteresis behaviour, which is comparable to that of a magnetic homogeneous square element. The exchange spring behaviour, occurring with increasing difference in M_s between the two phases, is related to an increase in effective shape anisotropy in the high M_s stripes. The magnetization reverses through an antiparallel alignment of magnetization of the individual stripes. The resulting lateral domain walls are stabilized by the inter-stripe flux closure. The two-step reversal is modelled by taking the demagnetization and domain wall energy terms into account. This work is funded by the German Science Foundation, project DFG: Mc 9/7