  We study the ferromagnetic phase transition in a randomly layered Heisenberg
model. A recent strong-disorder renormalization group approach [Phys. Rev. B
81, 144407 (2010)] predicted that the critical point in this system is of
exotic infinite-randomness type and is accompanied by strong power-law
Griffiths singularities. Here, we report results of Monte-Carlo simulations
that provide numerical evidence in support of these predictions. Specifically,
we investigate the finite-size scaling behavior of the magnetic susceptibility
which is characterized by a non-universal power-law divergence in the Griffiths
phase. In addition, we calculate the time autocorrelation function of the
spins. It features a very slow decay in the Griffiths phase, following a
non-universal power law in time.
