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arXiv · 1311.7660

Generation linewidth of mode-hopping spin torque oscillators

Ezio Iacocca·Olle Heinonen·P. K. Muduli·Johan Åkerman
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Abstract

Experiments on spin torque oscillators commonly observe multi-mode signals. Recent theoretical works have ascribed the multi-mode signal generation to coupling between energy-separated spin wave modes. Here, we analyze in detail the dynamics generated by such mode coupling. We show analytically that the mode-hopping dynamics broaden the generation linewidth and makes it generally well described by a Voigt lineshape. Furthermore, we show that the mode-hopping contribution to the linewidth can dominate in which case it provides a direct measure of the mode-hopping rate. Due to the thermal drive of mode-hopping events, the mode-hopping rate also provides information on the energy barrier separating modes and temperature-dependent linewidth broadening. Our results are in good agreement with experiments, revealing the physical mechanism behind the linewidth broadening in multi-mode spin torque oscillators.

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Ezio Iacocca, Olle Heinonen, P. K. Muduli, Johan Åkerman. 2013-11-29. Generation linewidth of mode-hopping spin torque oscillators. https://doi.org/10.1103/physrevb.89.054402

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