  In this work, we leverage atomistic spin-lattice simulations to examine how
magnetic interactions impact the propagation of sound waves through a
ferromagnetic material. To achieve this, we characterize the sound wave
velocity in BCC iron, a prototypical ferromagnetic material, using three
different approaches that are based on the oscillations of kinetic energy,
finite-displacement derived forces, and corrections to the elastic constants,
respectively. Successfully applying these methods within the spin-lattice
framework, we find good agreement with the Simon effect including high order
terms. In analogy to experiments, morphic coefficients associated with the
transverse and longitudinal waves propagating along the [001] direction are
extracted from fits to the fractional change in velocity data. The present
efforts represent an advancement in magnetoelastic modelling capabilities which
can expedite the design of future magneto-acoustic devices.

Materials Science