Regensburg 2007 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 12: Spindependent Transport I

MA 12.7: Vortrag

Dienstag, 27. März 2007, 11:45–12:00, H22

Current induced domain wall motion and domain wall transformations observed with XMCDPEEM — •Lutz Heyne, Dirk Backes, Markus Laufenberg, Mathias Kläui, and Ulrich Rüdiger — Universität Konstanz, 78457 Konstanz

While current-induced domain wall motion (CIDM) has been known theoretically [1] as well as experimentally, only recently controlled current-induced motion of single domain walls has been observed.

In this work we investigate CIDM in zig-zag permalloy wires of different dimensions. To image the magnetization configuration, x-ray magnetic circular dichroism photoemission electron microscopy (XMCDPEEM) is used. By imaging the magnetization contribution we can estimate an average domain wall (DW) velocity and directly observe spin-torque induced transformations of the internal DW structure.

In thick wires we observe a spin-torque induced nucleation and annihilation of magnetic vortices. The velocity is found to be directly correlated to these transformations [2]. Depending on the wire dimensions, several DW configurations are stable. A periodic transformation of the DW under current from vortex to transverse and vice versa is predicted by theory [3]. In a wire where both configurations can coexist we succeeded to image different DW configurations after the current pulses in agreement with theory, we also saw intermediate states, showing the actual transformation from transverse to vortex walls.

[1] C.H. Marrows, Adv. Phys. 54 585 (2005).

[2] M. Kläui, et al., Appl. Phys. Lett. 88, 232507 (2006).

[3] A. Thiaville et al., Europhys. Lett. 69, 990 (2005);