We discuss the coherence of magnetic oscillations in a magnetic tunnel junction-based spin-torque oscillator as a function of external field angle. Time-frequency analysis shows mode-hopping between distinct oscillator modes, which arises from linear and nonlinear couplings in the Landau-Lifshitz-Gilbert equation, analogous to mode-hopping observed in semiconductor ring lasers. These couplings and therefore mode-hopping are minimized near the current threshold for antiparallel (AP) alignment of free layer with reference layer magnetization. Away from the AP alignment, mode-hopping limits oscillator coherence.
@article{arxiv.1203.6300,
title = {Decoherence and mode-hopping in a magnetic tunnel junction-based spin-torque oscillator},
author = {P. K. Muduli and O. G. Heinonen and J. Åkerman},
journal= {arXiv preprint arXiv:1203.6300},
year = {2012}
}
Comments
To appear in Phys. Rev. Lett. Note the paper accompany Suppl info