  Harnessing the causal relationships between mechanical and magnetic
properties of van der Waals materials presents a wealth of untapped opportunity
for scientific and technological advancement, from precision sensing to novel
memories. This can, however, only be exploited if the means exist to
efficiently interface with the magnetoelastic interaction. Here, we demonstrate
acoustically-driven spin-wave resonance in a crystalline antiferromagnet,
chromium trichloride, via surface acoustic wave irradiation. The resulting
magnon-phonon coupling is found to depend strongly on sample temperature and
external magnetic field orientation, and displays a high sensitivity to
extremely weak magnetic anisotropy fields in the few~mT range. Our work
demonstrates a natural pairing between power-efficient strain-wave technology
and the excellent mechanical properties of van der Waals materials,
representing a foothold towards widespread future adoption of dynamic
magneto-acoustics.
