Regensburg 2010 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 17: Spin Dynamics / Spin Torque II

MA 17.3: Vortrag

Mittwoch, 24. März 2010, 15:00–15:15, H10

Dynamics of massless magnetic domain walls in cylindrical Permalloy nanowires — •Ming Yan, Attila Kákay, Sebastian Gliga, and Riccardo Hertel — Institut für Festkörperforschung, IFF-9, Forschungszentrum Jülich, D-52425 Jülich

It is well known that there exists an upper limit to the velocity of magnetic domain walls (DWs) driven by an external force. This is related to the accumulation of energy or, in other words, the increase of effective mass of the DW during its motion. We have found that DWs formed in cylindrical nanowires can be effectively massless, such that their velocity is not limited by these effects [1]. Driven by a magnetic field or a spin polarized electric current, this DW-type propagates along a characteristic spiraling path. Owing to the cylindrical symmetry of the wire, the DW maintains its configuration during its motion, thereby avoiding the accumulation of energy. This type of DW may have important implications in fundamental studies and for applications, especially in the case of current-driven DW motion. We show that the spin polarization rate of the current can be directly determined by measuring the DW velocity. Moreover, the rotational motion of the DW can be used to measure the non-adiabatic spin transfer torque parameter. The smooth linear motion of the DW provides a possibility to achieve precisely controlled DW motion, which is essential for race-track memories [2].

References:

[1] M. Yan, A. Kákay, S. Gliga, and R. Hertel, submitted.

[2] S. S. Parkin, M. Hayashi, and L. Thomas, Science 320, 190 (2008).