  The ability to modify and tune the spin-wave dispersion is one of the most
important requirements for engineering of magnonic networks. In this study we
demonstrate the promise of synthetic thin-film hybrids composed of an
antiferromagnetic insulator (AF) and a normal (N) or superconducting (S) metal
for tuning and modifying the spin-wave dispersion in antiferromagnetic
insulators. The key ingredient is the uncompensated magnetic moment at the
AF/S(N) interface, which induces an effective exchange field in the adjacent
metal via the interface exchange interaction. The exchange field spin polarizes
quasiparticles in the metal and induces spinful triplet Cooper pairs screening
the magnon. The quasiparticle and Cooper pair polarization renormalizes the
magnon dispersion. The renormalization results in the splitting of the
otherwise degenerate AF magnon modes with no need to apply a magnetic field. It
is also proposed that measurements of the renormalized dispersion relations can
provide the amplitude of the effective exchange field induced by the AF in the
adjacent metal.
