Frequency modulation experiments were performed on a spin torque vortex oscillator for a wide range of modulation frequency, up to 10 % of the oscillator frequency. A thorough analysis of the intermodulation products shows that the key parameter that describes these experiments is the deviation sensitivity, which is the dynamical frequency-current dependence. It differs significantly from the oscillator tunability discussed so far in the context of spin-transfer oscillators. The essential difference between these two concepts is related to the response time of the vortex oscillator, driven either in quasi-steady state or in a transient regime.
@article{arxiv.1306.5552,
title = {Tunability versus deviation sensitivity in a non-linear vortex oscillator},
author = {S. Y. Martin and C. Thirion and C. Hoarau and C. Baraduc and B. Diény},
journal= {arXiv preprint arXiv:1306.5552},
year = {2013}
}