Dresden 2009 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 25: Micro- and Nanostructured Magnetic Materials II

MA 25.2: Vortrag

Mittwoch, 25. März 2009, 15:00–15:15, HSZ 403

Magnetization Reversal of Electrochemically Synthesized Nanowires — •Judith Moser, Tim Böhnert, Kristina Pitzschel, Robert Zierold, Lars Bocklage, Michael Martens, Shadyar Farhangfar, Ulrich Merkt, Kornelius Nielsch, and Guido Meier — Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg

We suggest novel nanostructures for spin momentum transfer studies. The electrodeposition of ferromagnetic materials in self-organized pores of an Al₂O₃-membrane provides the unique ability to process ultrathin wires of complex shape and with reproducible properties [1]. For both fundamental research and technological applications it is of interest to understand the pinning and the dynamics of domain walls as well as the interaction between domain walls and spin-polarized currents in such nanostructures [2]. We synthesize Ni nanowires with diameters between 30 nm and 300 nm and aspect ratios up to 500. The magnetization reversal of single wires is studied by magnetic-force microscopy (MFM), X-ray microscopy, and anisotropic magnetoresistance measurements in straight wires, in bent wires, and in wires with diameter modulations serving as tailored pinning sites. The angle dependence of the switching field is proportional to 1/cos(θ) and the MFM images support the idea of magnetization reversal via domain-wall motion.

[1] K. Nielsch et al., Handbook of Magnetism and Adv. Magnet. Mat., Vol. 4, John Wiley and Sons (2007). [2] G. Meier et al., Phys. Rev. Lett. 98, 187202 (2007).