We report on numerical analysis on self-oscillation of standing spin wave excited in a nanostructured active ring resonator, consists of a ferromagnetic nanowire with perpendicular anisotropy. The confined resonant modes are along the nanowire length. A positive feedback with proportional-integral-derivative gain control was adopted in the active ring. Stable excitation of the 1st order standing spin wave has been demonstrated with micromagnetic simulations, taking into account the thermal effect with a random field model. The stationary standing spin wave with a pre-determined set variable of precession amplitude was attained within 20ns by optimizing the proportional-integral-derivative gain control parameters. The result indicates that a monochromatic oscillation frequency fosc is extracted from the initial thermal fluctuation state and selectively amplified with the positive feedback loop. The obtained fosc value of 5.22GHz practically agrees with the theoretical prediction from dispersion relation of the magneto static forward volume wave. It was also confirmed that the fosc change due to the temperature rise can be compensated with an external perpendicular bias field Hb. The observed quick compensation time with an order of nano second suggests the fast operation speed in the practical device application.
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