Nonreciprocal Spin Cherenkov excitation induced by Dzyaloshinskii-Moriya interaction in ferromagnetic nanowires

Abstract

The Spin-Cherenkov Effect (SCE) is a spin wave (SW) excitation phenomenon that occurs when a disturbance in the magnetic system exceeds the minimum phase velocity of the SWs. In this study, we investigate the influence of bulk Dzyaloshinskii-Moriya interaction (DMI), an antisymmetric exchange interaction, on the SCE in quasi-three-dimensional permalloy nanostrips using micromagnetic simulations. Our results show that the SWs excited by moving magnetic pulses in the system exhibit notable nonreciprocity that is dependent on the strength of the bulk DMI. Furthermore, we demonstrate that applying a spin-polarized electric current can effectively manipulate this nonreciprocity. Analytical calculations accounting for the bulk DMI and spin transfer torque are in good agreement with our numerical results. The combination of DMI and an electric current provides an effective means for harnessing the nonreciprocal Cherenkov excitation of SWs, which may have potential applications in the development of magnonic devices.