Dresden 2009 – scientific programme
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MA: Fachverband Magnetismus
MA 30: Spin-Dynamics / Spin-Torque III
MA 30.1: Talk
Thursday, March 26, 2009, 10:15–10:30, HSZ 04
Current and Field Induced Domain-Wall Motion in Permalloy Nanowires — •Gesche Nahrwold1, Lars Bocklage1, Toru Matsuyama1, Jan M. Scholtyssek1, Benjamin Krüger2, Ulrich Merkt1, and Guido Meier1 — 1Universität Hamburg, Jungiusstr. 11, 20355 Hamburg — 2Universität Hamburg, Jungiusstr. 9, 20355 Hamburg
Magnetic domain walls (DWs) in nanowires have attracted a lot of interest because of their possible application in logic and memory devices [1]. We present results obtained in curved permalloy wires where DWs are pushed by ns current pulses. By an externally applied magnetic field the DW is generated in the curved region of the wire. Measurements of the anisotropic magnetoresistance verify the presence of the wall. The resistance values before and after a current pulse indicate whether the DW has been depinned and moved out of the wire or not. Motivated by the pioneering work of L. Thomas et al. [2] we are able to measure the oscillatory dependence of the depinning behaviour of DWs on the pulse length with a characteristic frequency of 267 MHz if the current induced force on the DW is aligned opposite to the applied background field. The quality of the utilized permalloy for these experiments is crucial for their success. By sputtering permalloy on heated substrates we are able to considerably decrease the specific resistance, that is assumed to directly correspond to unwanted pinning centres for the DW. [1] S. S. P. Parkin et al., Science 320, 190 (2008), [2] L. Thomas et al., Nature 443, 197 (2006).