Domain wall propagation through spin wave emission

We theoretically study field-induced domain wall (DW) motion in an electrically insulating ferromagnet with hard- and easy-axis anisotropies. Different from the common wisdom, we prove that a DW in a dissipationless wire with a finite transverse magnetic anisotropy can propagate along the wire. The DW subjected to an external magnetic field undergoes a periodic transformation that excites SWs. The energy carried away must be compensated by the Zeeman energy that is released by DW propagation. Thus, a domain wall propagation mode through spin wave emission is revealed. The DW propagation locked into the known soliton velocity at low fields. In the presence of small damping, the usual Walker rigid-body propagation mode may become unstable for magnetic fields below the Walker breakdown.