Adjusting spectrum gaps of spin waves by interference

The spin waves have attracted huge interest in recent years due to the possibility to use spin waves to excite, transfer and process electric signals. The application depends on the ability to manipulate the propagation of spin waves. Using the principle of Bragg refection, the periodic magnetic nano-structures have been introduced to manipulate the dispersion relations of propagating spin waves by causing a forbidden band at Brillouin zone boundaries [1]. However, the spin waves in these periodic structures always reflect at the Brillouin zone boundaries, resulting in an increase of the transmission loss and a decrease of the propagation distance. On the other hand, fabrication of periodic nanostructures involves high-precision electron-beam lithography which is very complex and expensive. In our previous studies, we present a way to manipulate spin waves by interference in a uniform waveguide rather than by traditional Bragg reflection in periodic structure waveguide [2]. We studied the effect of the distance, number and width of the excitation sources on spectrum gaps in detail. However, how to manipulate dynamically spin waves in a waveguide is still an intriguing project so far. In this work, we present a new way to modulate dynamically the spin wave propagation by interference.