  Spincurrentronics, which involves the generation, propagation and control of
spin currents, has attracted a great deal of attention because of the
possibility of realizing dissipation-free information propagation. Whereas
electrical generation of spin currents originally made the field of
spincurrentronics possible, and significant advances in spin-current devices
has been made, novel spin-current-generation approaches such as dynamical
methods have also been vigorously investigated. However, the low spin-current
generation efficiency associated with dynamical methods has impeded further
progress towards practical spin devices. Here we show that by introducing a
Heusler-type ferromagnetic material, Fe3Si, pure spin currents can be generated
about twenty times more efficiently using a dynamical method. This achievement
paves the way to the development of novel spin-based devices.
