  We theoretically investigate the transfer of angular momentum between a spin
superfluid and a domain wall in an exchange coupled easy-axis and easy-plane
magnetic insulator system. A domain wall in the easy-axis magnet absorbs spin
angular momentum via disrupting the flow of a superfluid spin current in the
easy-plane magnet. Focusing on an open geometry, where the spin current is
injected electrically via a nonequilibrium spin accumulation, we derive
analytical expressions for the resultant superfluid-mediated motion of the
domain wall. The analytical results are supported by micromagnetic simulations.
The proposed phenomenon extends the regime of magnon-driven domain-wall motion
to the case when the magnons are condensed and exhibit superfluidity.
Furthermore, by controlling the pinning of the domain wall, we propose a
realization of a reconfigurable spin transistor. The long-distance
dissipationless character of spin superfluids can thus be exploited for
manipulating soliton-based memory and logic devices.
