Yttrium iron garnet (YIG) is a prototypical material in spintronics due to
its exceptional magnetic properties. To exploit these properties high quality
thin films need to be manufactured. Deposition techniques like sputter
deposition or pulsed laser deposition at ambient temperature produce amorphous
films, which need a post annealing step to induce crystallization. However, not
much is known about the exact dynamics of the formation of crystalline YIG out
of the amorphous phase. Here, we conduct extensive time and temperature series
to study the crystallization behavior of YIG on various substrates and extract
the crystallization velocities as well as the activation energies needed to
promote crystallization. We find that the type of crystallization as well as
the crystallization velocity depend on the lattice mismatch to the substrate.
We compare the crystallization parameters found in literature with our results
and find an excellent agreement with our model. Our results allow us to
determine the time needed for the formation of a fully crystalline film of
arbitrary thickness for any temperature
