This paper shows that the presence of two dynamical regimes, characterized by different precessional-axis, is the origin of the non-monotonic behavior of the output integrated power for large-amplitude magnetization precession driven by spin-polarized current in nanoscale exchange biased spin-valves. In particular, at the transition current between those two regimes exists an abruptly loss in the integrated output power. After the introduction of a time-frequency analysis of magnetization dynamics based on the wavelet transform, we performed a numerical experiment by means of micromagnetic simulations. Our results predicted that, together with a modulation of the frequency of the main excited mode of the magnetization precession, at high non-linear dynamical regime the instantaneous output power of the spin-torque oscillator can disappear and then reappear at nanosecond scale.
@article{arxiv.0903.2751,
title = {Non-stationary magnetization dynamics driven by spin transfer torque},
author = {G. Siracusano and G. Finocchio and A. La Corte and G. Consolo and L. Torres and B. Azzerboni},
journal= {arXiv preprint arXiv:0903.2751},
year = {2009}
}
Comments
10 pages 4 figures, to be appear in Physical Review B