Modulating spin wave nonreciprocity via frequency modification on width-controlled waveguide

Abstract

pin wave generated from antenna have different amplitude for the direction of propagation. This phenomenon is called spin wave nonreciprocity, and it is a unique characteristic compared to other electromagnetic signals. In this study, spin wave nonreciprocity of permalloy wire is modified by modulating RF excitation frequency. To obtain high spin wave nonreciprocity, peak frequency of propagating wave for each direction was controlled by varying the width of the permalloy waveguide. Width of the waveguide were selected by 1.6 and 3 μm for each direction. RF excitation frequency was scanned from 6.0 to 9.0 GHz and spin wave propagation was observed for each frequency. Spin wave propagation in permalloy waveguide was mapped and the reasons for the propagating shape were also studied. The spin wave intensity ratio of top side to bottom side could be controlled from 0.252 to 3.366 with relevant intensity. Every experiment was performed by micro-focused Brillouin light scattering, to obtain high lateral resolution. This study is expected to play a key role in comprising spin wave logic device.