  In antiferromagnets, the efficient propagation of spin-waves has until now
only been observed in the insulating antiferromagnet hematite, where circularly
(or a superposition of pairs of linearly) polarized spin-waves propagate over
long distances. Here, we report long-distance spin-transport in the
antiferromagnetic orthoferrite YFeO$_3$, where a different transport mechanism
is enabled by the combined presence of the Dzyaloshinskii-Moriya interaction
and externally applied fields. The magnon decay length is shown to exceed
hundreds of nano-meters, in line with resonance measurements that highlight the
low magnetic damping. We observe a strong anisotropy in the magnon decay
lengths that we can attribute to the role of the magnon group velocity in the
propagation of spin-waves in antiferromagnets. This unique mode of transport
identified in YFeO$_3$ opens up the possibility of a large and technologically
relevant class of materials, i.e., canted antiferromagnets, for long-distance
spin transport.
