Magnonic frequency combs based on the resonantly enhanced magnetostrictive effect.

A magnonic counterpart to optical frequency combs is vital for high-precision magnonic frequency metrology and spectroscopy. Here, we present an efficient mechanism for the generation of robust magnonic frequency combs in a yttrium iron garnet (YIG) sphere via magnetostrictive effects. We show that magnonic and vibrational dynamics in the ferrimagnetic sphere can be substantively modified in the presence of magnetostrictive effects, which results in degenerate and non-degenerate magnonic four-wave mixing and frequency conversion. Particularly, resonantly enhanced magnetostrictive effects can induce phonon laser action above a threshold, which leads to significant magnonic nonlinearity and enables a potentially practical scheme for the generation of robust magnonic frequency combs. Numerical calculations of both magnonic and phononic dynamics show excellent agreement with this theory. These results deepen our understanding of magnetostrictive interaction, open a novel and efficient pathway to realize magnonic frequency conversion and mixing in a magnonic device, and provide a sensitive tool for precision measurement.