Temperature dependence of linewidth in nanocontact based spin torque oscillators: Effect of multiple oscillatory modes
2012 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 86, no 17, 174408- p.Article in journal (Refereed) Published
We discuss the effect of mode transitions on the current (I) and temperature (T) dependent linewidth (Delta f) in nanocontact based spin torque oscillators (STOs). At constant I, Delta f exhibits an anomalous temperature dependence near the mode transitions; Delta f may either increase or decrease with T depending on the position w.r.t. the mode transition. We show that the behavior of Delta f as a function of I can be fitted by the single mode analytical theory of STOs, even though there are two modes present near the mode transition, if the nonlinear amplification is determined directly from the experiment. Using a recently developed theory of two coupled modes, we show that the linewidth near mode transition can be described by an "effective" single-oscillator theory with an enhanced nonlinear amplification that carries additional temperature dependence, which thus qualitatively explain the experimental results.
Place, publisher, year, edition, pages
2012. Vol. 86, no 17, 174408- p.
Magnetic Multilayers, Microwave Generation, Polarized Current, Nano-Oscillators, Excitation, Waves, Modulation
IdentifiersURN: urn:nbn:se:kth:diva-107072DOI: 10.1103/PhysRevB.86.174408ISI: 000310683300007ScopusID: 2-s2.0-84869026027OAI: oai:DiVA.org:kth-107072DiVA: diva2:574978
FunderSwedish Research CouncilKnut and Alice Wallenberg Foundation
QC 201212072012-12-072012-12-062012-12-07Bibliographically approved