Analytical investigation of modulated spin-torque oscillators in the framework of coupled differential equations with variable coefficients
2012 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 85, no 18, 184420- p.Article in journal (Refereed) Published
Modulation of spin torque oscillators (STOs) is investigated by analytically solving the time-dependent coupled equations of an auto-oscillator. A Fourier-series solution is proposed, leading to the coefficients being determined with a linear set of equations, from which a nonlinear amplitude and frequency modulation (NFAM) scheme is obtained. In this framework, the NFAM features are related to the intrinsic STO parameters, revealing a frequency dependence of the harmonic-dependent modulation index that allows a modulation bandwidth to be defined for these devices. The presented results expose a rich parameter space, where the modulation and the STO's operation conditions define the observed modulation features. The Fourier-series representation of the time signal is suitable for studying periodic perturbations on the auto-oscillator equation.
Place, publisher, year, edition, pages
2012. Vol. 85, no 18, 184420- p.
Nano-Oscillators, Frequency-Modulation, Polarized Current, Phase-Locking, Excitation, Devices, Waves
IdentifiersURN: urn:nbn:se:kth:diva-98009DOI: 10.1103/PhysRevB.85.184420ISI: 000304393200005ScopusID: 2-s2.0-84861694892OAI: oai:DiVA.org:kth-98009DiVA: diva2:534643
FunderKnut and Alice Wallenberg FoundationSwedish Research Council
QC 201206182012-06-182012-06-182012-06-18Bibliographically approved