A scheme is proposed for steering the magnetization of a monodomain nanoparticle to a predefined state via ultrashort magnetic pulses. Based on the Landau-Lifshitz-Gilbert equation we find analytical expressions for the driving fields and the magnetization dynamics valid for pulse durations shorter than the field-free precessional period of the magnetization. These expressions do not depend on the type of anisotropy and provide conditions for fast switching and magnetization “freezing.” Numerically, using the Landau-Lifshitz-Gilbert equation extended to finite temperatures we confirm the robustness of the analytical predictions to thermal fluctuations, different anisotropy types, and shapes of pulses; and also explore the range of validity of the short-pulse approximation.

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(Reference: TH-2009-34)