The effect of van Hove singularities on spin pumping in the magnonic crystal/normal metal structure

Using the inverse spin Hall effect, spin pumping by magnetostatic backward volume waves (MSBVW) in a structure based on a magnonic crystal from an yttrium-iron garnet film and a Pt microstrip has been studied. A resonant increase in the EMF signal at the frequencies of Bragg resonances (BR) was detected, which reflects an increase in the efficiency of spin pumping. The resonant amplification of spin pumping is explained by an increase in the efficiency of electron-magnon scattering due to the formation of dispersion regions with a high density of van Hove singularities in the MSBVW spectrum at BR frequencies.