Reverse Doppler effect of magnons with negative group velocity scattered from a moving Bragg grating
Reverse Doppler effect of magnons with negative group velocity scattered from a moving Bragg grating
We report on the observation of reverse Doppler effect in backward spin waves reflected off of surface acoustic waves. The spin waves are excited in a yttrium iron garnet (YIG) film. Simultaneously, acoustic waves are also generated. The strain induced by the acoustic waves in the magnetostrictive YIG film results …