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MA: Fachverband Magnetismus

MA 7: Spin-Dynamics/ Spin-Torque II

MA 7.14: Vortrag

Montag, 23. März 2009, 18:45–19:00, HSZ 04

Local control of ultra fast dynamics in magnetic nanoparticles — •Alexander Sukhov^1,2 and Jamal Berakdar² — ¹Max-Planck-Institut für Mikrostrukturphysik, Halle/Saale — ²Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Halle/Saale

Using the local control theory [1] and the Landau-Lifshitz-Gilbert equation of magnetization motion for a Stoner nanoparticle we deduce analytical expressions for ultra short magnetic pulses that steer the magnetization to a predefined state. Additionally, we obtain conditions for a monotonic positive change of the polar angle providing thus a magnetization switching. Minimal field amplitudes of the pulses needed for switching upon the polar angle for two angle shifts between the magnetization and the field are achieved. Numerical implementation of the Landau-Lifshitz-Gilbert equation extended for finite temperatures allows for more freedom in variation of pulse form, duration and anisotropy types and approves/supplements the analytical results.
R. Kosloff, A. D. Hammerich and D. J. Tannor, Phys. Rev. Lett. 69, 2172 (1992).