The propagation characteristics of solitary spin waves in an yttrium iron garnet waveguide were investigated using a vector network analyzer and a real-time oscilloscope. Frequency- and time-domain analyses of spin-wave waveforms revealed the transition from linear to nonlinear response regimes and identified the threshold excitation power required to establish a single spin-wave soliton. With sufficiently high excitation power, a single spin-wave soliton transformed into a stable soliton train when the excitation frequency was modulated within dipole gaps. The frequency characteristics of the soliton train varied with the duration of the excitation power signal. The different time segments of the waveforms suggested the presence of new spin-wave modes excited through the self-modulation instability process, providing valuable insights into the formation of high-density spin-wave soliton trains.

  Generating chaos in spintronics devices has attracted much attention for the application of physical reservoir computing. We theoretically investigate the influence of the potential deformation due to the nanodisk structure on the magnetic vortex core dynamics in circular magnetic nanodisk. Considering a circular magnetic nanodisk with an additional disk, we numerically calculate the magnetic vortex dynamics using the Thiele equation. The deformation potential is modeled by using micromagnetic simulation. The chaos is induced by applying an AC magnetic field to the nanodisk with only an additional disk. In contrast, chaos disappears when the AC magnetic field is applied to a nanodisk without an additional disk.