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MA: Fachverband Magnetismus

MA 19: Micro Magnetism / Computational Magnetism

MA 19.9: Vortrag

Mittwoch, 25. März 2009, 12:15–12:30, HSZ 403

Annihilation of 360°-domain-walls by high-frequency magnetic field pulses. — •Felix Kurth, Rudolf Schäfer, Jeffrey McCord, and Ludwig Schultz — Leibniz Institute for Solid State and Materials Research IFW Dresden, P.O. Box 270116, 01171 Dresden, Germany

360°-domain-walls are metastable blocked domain walls in thin magnetic films. Such walls are only removable in external fields much higher than needed for regular 180° Neel-wall movement. In order to eliminate the walls magnetic fields up to 10 times the regular coercivity field of the system and well above the apparent saturation fields are necessary. The process of wall annihilation was studied by Kerr microscopy in the longitudinal mode in patterned Permalloy/Ta/CoFe (50 nm/4 nm/5 nm) thin magnetic double-layers. We were able to remove the 360° -walls by high-frequency magnetic field pulses significantly lower in amplitude than the quasi-static fields necessary for wall annihilation. The demonstrated route of 360°-wall annihilation by hf-pulses introduces a new path to homogenize the magnetization in patterned magnetic thin films for sensor applications. Possible annihilation mechanisms will be discussed.