Portal de Periódicos da CAPES

Self-Injection Locking of a Vortex Spin Torque Oscillator by Delayed Feedback

2016; Nature Portfolio; Volume: 6; Issue: 1 Linguagem: Inglês

10.1038/srep26849

2045-2322

Sumito Tsunegi, Eva Grimaldi, Romain Lebrun, Hitoshi Kubota, A. Jenkins, Kay Yakushiji, Akio Fukushima, Paolo Bortolotti, Julie Grollier, Shinji Yuasa, Vincent Cros,

Neural Networks and Reservoir Computing

Abstract The self-synchronization of spin torque oscillators is investigated experimentally by re-injecting its radiofrequency (rf) current after a certain delay time. We demonstrate that the integrated power and spectral linewidth are improved for optimal delays. Moreover by varying the phase difference between the emitted power and the re-injected one, we find a clear oscillatory dependence on the phase difference with a 2π periodicity of the frequency of the oscillator as well as its power and linewidth. Such periodical behavior within the self-injection regime is well described by the general model of nonlinear auto-oscillators including not only a delayed rf current but also all spin torque forces responsible for the self-synchronization. Our results reveal new approaches for controlling the non-autonomous dynamics of spin torque oscillators, a key issue for rf spintronics applications as well as for the development of neuro-inspired spin-torque oscillators based devices.