  The competition between shape and perpendicular magnetic anisotropies (PMA)
in magnetic thin films gives rise to unusual magnetic behaviors. In
ferromagnetic films with moderate PMA the magnetic domain configuration
transitions from planar to stripe-like domains above a critical thickness,
$t_c$. In this article, we present a detailed study of the magnetization
switching mechanism in FePt thin films, where this phenomenon is observed.
Using micromagnetic simulations and experiments, we found that below $t_c$ the
reversal mechanism is well described by the two-phase model while above this
thickness the magnetization within each stripe reverses by coherent rotation.
We also analyzed the PMA and its temperature dependence, probing that
substrate-induced strains are responsible for the abnormal coercive field
behavior observed for FePt films with $t>t_c$.
