Enhanced magnon transport through an amorphous magnetic insulator

Magnonics research is focused on the transport of spin information via spin-wave, or magnon, excitations. Due to its exceptionally low damping, the magnetic insulator Yttrium Iron Garnet (YIG) is considered the most prominent material in this field. New research has been stimulated by a report of long (µm) magnon diffusion lengths in amorphous YIG (a-YIG) where there is no long range magnetic order. Similar experiments have failed to reproduce the results and spin-pumping data provides a much lower (3.6nm) spin diffusion length. We have recently measured a 28nm spin diffusion length in a-YIG (28nm) and hypothesise that samples of a-YIG may differ depending on growth conditions. In this proposal we will use polarized neutron reflectometry to investigate a-YIG in order to see if deviations away from the expected M = 0 emu/cc can explain the longer spin diffusion length in our samples.