  The presence of interfacial Dzyaloshinskii-Moriya interaction (DMI) may lead
to the appearance of N\'eel skyrmions in ferromagnetic films. These
topologically protected structures, whose diameter is as small as a few
nanometers, can be nowadays stabilized at room temperature and have been
proposed for the realization of artificial magnonic crystals and new spintronic
devices, such as racetrack memories. In this perspective, it is of utmost
importance to analyze their dynamical properties in the GHz range, i.e. in the
operation range of current communication devices. Here we exploited the
software MuMax3 to calculate the dynamics of N\'eel skyrmions in the range
between 1 and 30 GHz, considering first the eigenmodes of an isolated skyrmion,
then the case of two interacting skyrmions and finally a linear chain,
representing a one-dimensional magnonic crystal, whose magnonic band structure
has been calculated as a function of the strength of both the DMI- and the
exchange-constants, namely D and A. The magnonic bands can be interpreted as
derived from the eigenmodes of isolated skyrmions, even if hybridization and
anti-crossing phenomena occur for specific ranges of values of D and A.
Therefore, varying the latter parameters, for instance by a proper choice of
the materials and thicknesses, may enable one to fine-tune the permitted and
forbidden frequency interval of the corresponding magnonic crystal.
