Influence of intersublattice coupling on the terahertz nutation spin dynamics in antiferromagnets

Spin nutation resonance has been well-explored in one-sublattice ferromagnets. Here, we investigate the spin two-sublattice antiferromagnets as well as, for comparison, ferrimagnets with inter-and intra-sublattice coupling. In particular, derive susceptibility of magnetic system response to an applied external field. To this end, antiferromagnetic and ferrimagnetic (sub-THz) precession THz frequencies are calculated. Our results show that effective damping decrease coupling, while they increase inter -sublattice antiferromagnet. However, find both intra-and inter-sublattice couplings. For ferrimagnets, conversely, calculate two modes distinct frequencies, unlike antiferromagnets. The exchange-like frequency decreases coupling increases like antiferromagnets, but ferromagnetic-like is practically invariant intra