Dynamic precursor effect: Magnitude-fluctuated coherent spin waves emitted by skyrmions

Abstract

Spin wave, a collective precessional motion of magnetizations, is the promising data carrier in spintronic devices due to its nanoscale and low-energy dissipation features. However, as a natural property, the magnitude variation of magnetizations inside spin waves is still unclear. Here, we emitted spin waves by rotating skyrmions, and detected a wave of fluctuated magnetization magnitude in the spin wave near the Curie temperature, which is defined as the “magnitude wave”. Then, we demonstrated such magnitude wave is coherent, and the coherence of magnitude waves triggers the emergence of new skyrmions at interference points, which shows the magnetic patterns can be predicted and even designed by the magnitude waves. Therefore, our study discovered the coherent magnitude wave hidden in spin waves, and revealed its coupling with magnetic patterns. It complements the intrinsic understanding of spin waves, and exploits an intriguing rich avenue for future research on magnetic dynamics.