Berlin 2008 – scientific programme

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MA: Fachverband Magnetismus

MA 9: Micromagnetism/Computational Magnetics

MA 9.3: Talk

Monday, February 25, 2008, 17:15–17:30, H 1012

Resonant and non-resonant current-induced vortex core switching — •Sebastian Gliga, Yaowen Liu, Riccardo Hertel, and Claus M. Schneider — Institut für Festkörperforschung (IFF-9), Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany

It has recently been demonstrated that the core of magnetic vortices in thin-film elements can be switched by in-plane electrical currents [1,2]. Presently, two distinct routes are known by which electric currents flowing in the sample plane can switch a magnetic vortex core. In the resonant switching, the gyrotropic mode of the vortex is excited by applying a sinusoidal electric current tuned at the corresponding frequency [1], typically below one GHz for mesoscopic thin film elements. In contrast, the non-resonant switching consists in applying a single current pulse [2] to trigger the core reversal within a few hundreds of picoseconds. Using fully three-dimensional micromagnetic simulations based on the finite-element method, we have compared the electrical core switching processes for both routes. We have found that the reversal is mediated by the temporary creation of a vortex-antivortex pair in both cases. Moreover, the core switching occurs as soon as the total and the exchange energies reach critical threshold values in the sample. These thresholds are the same for the resonant and the non-resonant cases, and do not depend on the amplitude of the applied current. The time needed to switch the vortex core thus depends on the rate at which the sample energy increases due to the applied current.

[1] K. Yamada et al., Nat. Mat. 6, 270 (2007)

[2] Y. Liu et al., Appl. Phys. Lett. 91, 112501 (2007)