Spin-torque nano-oscillators based on radial vortex in the presence of interface Dzyaloshinskii-Moriya interaction

Spin-torque and spin-Hall nano-oscillators based on topological magnetic solitons, including domain wall, circular vortex, Skyrmions and antiferromagnetic Skyrmions have sparked extensively scientific interest, which hold the advantage of miniature size, wideband tunability and high levels of integration with CMOS. Here, we present that the radial vortex state can also be brought into persistent self-oscillatory periodic motion by applying spin polarized current in a nanocontact cylinder magnetic multilayers structure. Using micromagnetic simulation, we show that the threshold current density of radial vortex oscillator is one order of magnitude lower than traditional spin-torque nano-oscillators. More importantly, the radial vortex oscillator exhibits roughly tripled time-varying averaged magnetization oscillation in comparison with the circular vortex oscillators. Therefore, the microwave output power can be greatly enhanced and the energy dissipation can be markedly reduced. The above-mentioned findings provide an in-depth knowledge of radial vortex oscillators, it may facilitate the practical application of radial vortex oscillators.