Regensburg 2010 – scientific programme

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MA: Fachverband Magnetismus

MA 17: Spin Dynamics / Spin Torque II

MA 17.5: Talk

Wednesday, March 24, 2010, 15:30–15:45, H10

Field and current driven depinning of domain walls in V-shaped nanowires — •Sebastian Hankemeier, Björn Beyersdorff, Robert Frömter, and Hans Peter Oepen — Universität Hamburg, Institut für Angewandte Physik, Jungiusstr. 11, 20355 Hamburg, Germany

We have studied the depinning behaviour of domain walls in V-shaped nanowires. In our geometry, the angle between the two arms of the Permalloy wire is 170^∘, width and thickness are 350 nm and 18 nm, respectively. At the intersection of the two arms, domain walls can be easily nucleated by an external field, which is aligned parallel to the mirror axis of the V-shaped wire. The electrical resistivity is measured to reveal the existence of a domain wall within the wire via the anisotropic magnetoresistance (AMR). The depinning behaviour of the domain wall has been investigated by measuring the AMR in dependence of strength and orientation of the external magnetic field. When cooling the nanowire, the DC current density can be increased up to 4 · 10¹² A/m² without destroying the wire [1]. Beyond a DC current density of 1 · 10¹¹ A/m², the current affects the depinning field of a domain wall via Joule heating, Oersted field and the spin torque effect. We demonstrate a procedure that allows a separation of these effects to study their individual influences on the depinning field of the domain wall. This work is supported by DFG, SFB 668.

[1] S. Hankemeier, K. Sachse, Y. Stark, R. Frömter, and H. P. Oepen, Appl. Phys. Lett. 92, 242503 (2008).