Driven energy transfer between coupled modes in spin-torque oscillators

Abstract

The mutual interaction between the different eigenmodes of a spin-torque oscillator can lead to a large variety of physical mechanisms from mode hopping to multi-mode generation, that usually reduce their performances as radio-frequency devices. To tackle this issue for the future applications, we investigate the properties of a model spin-torque oscillator that is composed of two coupled vortices with one vortex in each of the two magnetic layers of the oscillator. In such double-vortex system, the remarkable properties of energy transfer between the coupled modes, one being excited by spin transfer torque while the second one being damped, result into an alteration of the damping parameters. As a consequence, the oscillator nonlinear behavior is concomitantly drastically impacted. This efficient coupling mechanism, driven mainly by the dynamic dipolar field generated by the spin transfer torque induced motion of the vortices, gives rise to an unexpected dynamical regime of self-resonance excitation. These results show that mode coupling can be leveraged for controlling the synchronization process as well as the frequency tunability of spin-torque oscillators.

arXiv comment7 pages, 5 figures

References in corpus (23)

• Microwave Oscillations of a Nanomagnet Driven by a Spin-Polarized Current
• Dynamically encircling exceptional points in a waveguide: asymmetric mode switching from the breakdown of adiabaticity
• Topological energy transfer in an optomechanical system with exceptional points
• Spin torque building blocks
• Coherent phonon manipulation in coupled mechanical resonators
• Generation of coherent spin-wave modes in Yttrium Iron Garnet microdiscs by spin-orbit torque
• Synchronization of spin-transfer oscillators driven by stimulated microwave currents
• Generation linewidth of an auto-oscillator with a nonlinear frequency shift: Spin-torque nano-oscillator
• Dynamics of coupled vortices in a pair of ferromagnetic disks
• Bistability of vortex core dynamics in a single perpendicularly magnetized nano-disk
• Dynamics of two coupled vortices in a spin valve nanopillar excited by spin transfer torque
• Identification and selection rules of the spin-wave eigen-modes in a normally magnetized nano-pillar
• Tunable energy transfer between dipolar-coupled magnetic disks by stimulated vortex gyration
• Understanding of phase noise squeezing under fractional synchronization of non-linear spin transfer vortex oscillator
• Decoherence and mode-hopping in a magnetic tunnel junction-based spin-torque oscillator
• Origin of spectral purity and tuning sensitivity in a vortex-based spin transfer nano-oscillator
• Perfect and robust phase-locking of a spin transfer vortex nano-oscillator to an external microwave source
• Measurement of the dynamical dipolar coupling in a pair of magnetic nano-disks using a Ferromagnetic Resonance Force Microscope
• Generation linewidth of mode-hopping spin torque oscillators
• Nonlinear behavior and mode coupling in spin transfer nano-oscillators
• Parallel pumping of magnetic vortex gyrations in spin-torque nano-oscillators
• Temperature dependence of linewidth in nano-contact based spin torque oscillators: effect of multiple oscillatory modes
• Transition from one- to two-mode generation regime in spin-torque nano-oscillator mediated by thermal noise