Abstract
The switching times of submicron-sized magnets are of the order of pico-to nanoseconds. The switching speed is controlled by the geometric shape of the magnets, the intrinsic magnetic properties, and the orientation and strength of the applied field. Precessional motion governs the switching dynamics of small magnetic particles. If the rise time of the external field is faster than the relaxation of the magnetization toward the nearest local minimum, fast switching of particles is possible in fields below the anisotropy field. The switching speed of thin-film elements depends on the reversal mode. Two distinct reversal modes are found: (1) nucleation and expansion of reversed domains and (2) nonuniform rotation of the magnetization. Domain nucleation occurs in randomly oriented, granular hcp-Co thin films and granular CoCrPt elements with perpendicular anisotropy. Rotational processes are found in granular fcc-Co thin films. The switching by rotation is about four times faster than switching by nucleation and expansion of domains. Switching by rotation can be enforced by applying a sufficiently large rotational field. Thermal activation decreases switching time.
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Schrefl, T. et al. (2003). Fast Switching of Mesoscopic Magnets. In: Hillebrands, B., Ounadjela, K. (eds) Spin Dynamics in Confined Magnetic Structures II. Topics in Applied Physics, vol 87. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-46097-7_1
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DOI: https://doi.org/10.1007/3-540-46097-7_1
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