Channeling of spin waves in antiferromagnetic domain walls

We theoretically calculated ultrafast propagations of spin waves channeled in antiferromagnetic Bloch-type domain walls based on a phenomenological theory developed by Hals et al. [Phys. Rev. Lett. 106, 107206 (2011)]. Our analytical derivation demonstrates that the dispersion relation of such channeled spin waves exhibits an extremely high group velocity, up to \ensuremath{\sim}18.7 km/s, without any forbidden gap. Further, such electromagnetic-wave-like dispersion relation allows for dispersionless and translational transmission of trains of low-frequency, long-wavelength digital signals in the channel. Our results offer guidelines for the development of ultrafast information signal processing in nanoscale magnonic circuits composed of antiferromagnetic domain walls.