Spin-Hall nano-oscillator with oblique magnetization and Dzyaloshinskii-Moriya interaction as generator of skyrmions and nonreciprocal spin-waves

摘要

Spin-Hall oscillators (SHO) are promising sources of spin-wave signals for magnonics applications,\udand can serve as building blocks for magnonic logic in ultralow power computation devices. Thin\udmagnetic layers used as “free” layers in SHO are in contact with heavy metals having large spinorbital\udinteraction, and, therefore, could be subject to the spin-Hall effect (SHE) and the interfacial\udDzyaloshinskii-Moriya interaction (i-DMI), which may lead to the nonreciprocity of the excited\udspin waves and other unusual effects. Here, we analytically and micromagnetically study\udmagnetization dynamics excited in an SHO with oblique magnetization when the SHE and i-DMI\udact simultaneously. Our key results are: (i) excitation of nonreciprocal spin-waves propagating\udperpendicularly to the in-plane projection of the static magnetization; (ii) skyrmions generation by\udpure spin-current; (iii) excitation of a new spin-wave mode with a spiral spatial profile originating from a gyrotropic rotation of a dynamical skyrmion. These results demonstrate that SHOs can be\udused as generators of magnetic skyrmions and different types of propagating spin-waves for\udmagnetic data storage and signal processing applications.