Dynamics of ferrimagnetic domain walls driven by sinusoidal microwave magnetic field

Abstract

Ferrimagnetic domain walls have received more and more attention because of their interesting physics and potential applications in future spintronic devices, particularly attributing their non-zero net magnetization and ultrafast dynamics. Exploring effective methods of driving domain walls with low energy consumption and high efficiency can provide important information for experimental design and device development. In this work, we study theoretically and numerically the dynamics of ferrimagnetic domain wall driven by the sinusoidal microwave magnetic field using the collective coordinate theory and Landau-Lifshitz-Gilbert simulations of atomistic spin model. It is revealed that the microwave field drives the propagation of the domain wall when the frequency falls into an appropriate range, which allows one to modulate the domain wall dynamics through tuning field frequency. Specifically, below the critical frequency, the domain wall velocity is proportional to the field frequency and the net angular momentum, while above the critical frequency, the domain wall velocity decreases rapidly to zero . The physical mechanisms of the results are discussed in detail, and the influences of the biaxial anisotropy and other parameters on the velocity of domain wall are studied. It is suggested that the wall dynamics can be effectively regulated by adjusting the basic magnetic structure and magnetic anisotropy, in addition to the external microwave field frequency. This work uncovers the interesting dynamics of ferrimagnetic domain wall driven by sinusoidal microwave magnetic field, which is helpful for designing domain wall-based spintronic device.