We report vortex matching phenomenon in rectangular antidot array fabricated
on epitaxial NbN thin film. The antidot array was fabricated using Focussed Ion
Beam milling technique. The magneto-transport measurements points to a period
doubling transition at higher magnetic field for rectangular lattices. The
results are discussed within the light of several models including the
multi-vortex model, the matched lattice model and the super-matched lattice
model.Comment: Added references, modified abstract and discussions and corrected
typo-graphic errors. Accepted for proceedings of M2S-IX 2009, Tokyo (Physica
C