  The study concerns dynamics of standing spin waves in arrays of sub-100 nm
elliptic synthetic-antiferromagnet (SAF) nanodisks. We performed a detailed
ferromagnetic resonance analysis in conjunction with micromagnetic modeling to
find out several prominent traits of such systems. One broad line is shown to
be the sole resonant response for a SAF of the considered sizes. We demonstrate
that this mode is degenerated, and its excitation map resembles a superposition
of in-center and edge-type oscillations. We also show how this hybrid
excitation leads to almost twofold enhancement in the shape-induced anisotropy
of the mode.
