Self-stabilizing spin superfluid

Spin superfluidity is sought after as a potential route to long-range spin transport in ordered spin systems. Signatures of spin superfluidity have recently been observed in antiferromagnets, however, dipolar interactions have been predicted to destabilize the superfluid state and its realization in ferromagnets remains a challenge. Using micromagnetic simulations, we find that spin superfluidity can in fact be achieved in extended thin ferromagnetic films. We identify two unconventional superfluid states beyond the Landau instability. We uncover a surprising two-fluid state, in which spin superfluidity co-exists with and is stabilized by spin waves, as well as a soliton-screened superfluid at high biases. The results of this study advance our understanding of spin superfluidity and provide guidance for its experimental realization.