Spin transport of chiral magnons in ferrimagnet-antiferromagnet heterostructures

In this work, we theoretically study the spin transport of different chiral magnons injected from a ferrimagnet to an antiferromagnet with interfacial spin canting and present a chirality-dependent magnon transport. Specifically, we find that the penetration length of the right-handed magnons can be either longer or shorter than that of the left-handed ones, depending on whether the interfacial coupling is antiferromagnetic or ferromagnetic. This phenomenon is attributed to the mode match between the chiral magnons and the right-handed dynamics of the net magnetization in the canted antiferromagnet. The explicit values of the magnon penetration lengths are found to depend on the penetration length of the canting angle instead of its magnitude and hence can be efficiently modulated by the exchange parameters in the antiferromagnet, while the strength of the interfacial exchange coupling plays a minor role. This result suggests antiferromagnets with a larger penetration length of interfacial canting, corresponding to a larger intrasublattice ferromagnetic coupling, is favored for the chirality-sensitive magnon transport, which could be useful in chirality-based magnonics.