4 Reports on Experimental Results 4.2 Parametrical recovery of a spin-wave signal stored in amagnonic crystal

In the last years the storage and recovery of microwave signals in a tangentially magnetized mag-netic ferrite film using standing dipole-exchange spin-wave modes have been experimentally dis-covered and theoretically interpreted [1, 2]. The inherent standing spin-wave modes exist in mag-netic films due to the spatial confinement of the spin waves caused by the finite film thickness. Interaction between propagating surface magnetostatic spin waves and discrete standing spin-wave modes was used for the storage of a microwave signal in the magnetic film. The storage mecha-nism can take place only for the case of nonreciprocal surface spin waves, which have a natural hybridization with standing spin-wave modes in the plane film. Within this condition, the storage and recovery of a microwave signal are possible only if the signal frequency is equal to one of a standing wave modes. In order to overcome this feature and to make storage-recovery effects more general, we pro-posed to utilize an artificial medium with periodic lateral variations in their magnetic properties- magnonic crystals (MCs) [3–5]. Spin-wave spectra in such structures are significantly different from those of uniform media and exhibit features such as band gaps, where spin wave propagation is prohibited. Traveling spin waves that satisfy the Bragg condition for the MC lattice constant are not allowed to propagate and will be reflected. In the case of an ideal MC, the group velocity o