  In a coupled ferroelectric/ferromagnetic system, i.e. a composite
multiferroic, the propagation of magnetic or ferroelectric excitations across
the whole structure is a key issue for applications. Of a special interest is
the dynamics of localized magnetic or ferroelectric modes (LM) across the
ferroelectric-ferromagnetic interface, particularly when the LM's carrier
frequency is in the band of the ferroelectric and in the band gap of the
ferromagnet. For a proper choice of the system's parameters, we find that there
is a threshold amplitude above which the interface becomes transparent and a
band gap ferroelectric LM penetrates the ferromagnetic array. Below that
threshold, the LM is fully reflected. Slightly below this transmission
threshold, the addition of noise may lead to energy transmission, provided that
the noise level is not too low nor too high, an effect that resembles
stochastic resonance. These findings represent an important step towards the
application of ferroelectric and/or ferromagnetic LM-based logic.
