Magnonic crystal as a medium with tunable disorder on a periodical lattice.

We show that periodic magnetic nanostructures represent a perfect system for studying excitations on disordered periodical lattices because of the possibility of controlled variation of the degree of disorder by varying the applied magnetic field. Magnetic force microscopy images and ferromagnetic resonance (FMR) data collected inside minor hysteresis loops for a periodic array of Permalloy nanowires were used to demonstrate correlation between the type of FMR response and the degree of disorder of the magnetic ground state.