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The features of standing spin waves (SWs) excited during ferromagnetic resonance in three different one-dimensional magnonic crystals (MC) are intensively studied. The investigated magnonic crystals were: an array of air-spaced cobalt stripes, an array of air-spaced permalloy (Py) stripes, and a bi-component MC composed of alternating Co and Py stripes. All MC structures were made by etching technique from Co and Py thin films deposited onto Si substrates. Two configurations are considered with the in-plane external magnetic field applied parallel or perpendicular to the stripes. The supporting calculations are performed by the finite element method in the frequency domain. A number of intensive SW modes occurred in periodic structures under ferromagnetic resonance conditions as a consequence of standing spin waves excitation. These modes were analyzed theoretically in order to explain the origins of SW excitations. With the support of numerical calculations, we analyze also the possible scenarios for the occurrence of standing SWs in the investigated structures. It is demonstrated that the SW propagation length is an important factor conditioning the standing SW formation in MCs.

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The focusing effect for spin waves excited by a curved micrometer-sized coplanar waveguide transducer on top of a 5-μm-thick epitaxial yttrium iron garnet film is studied by means of the micro-focused Mandelstam-Brillouin light scattering technique and micromagnetic simulations. The curvilinear transducer is designed to focus the backward volume spin waves on the in-plane bias magnetic field applied along the symmetry axis of the transducer. We show that two-dimensional maps of spin wave intensity exhibit nonreciprocal properties without mirror symmetry with respect to the magnetic field direction and the focusing effect. The observed effects are the consequence of nonreciprocity of the backward volume spin waves travelling at an angle toward the bias field direction.

We report on the experimental observation of a spin wave (SW) propagation in a magnetic film lying on a developed surface—a three-dimensional (3D) magnonic structure. The 3D magnonic structure was fabricated by deposition of a 180  nm thick yttrium iron garnet film on the patterned substrate with a one-dimensional array of 1.5 μm deep grooves with the period of 20 μm using ion beam sputtering. We experimentally explored SW propagation in such a periodic structure for Bragg and Laue geometries. Transmission characteristics showed that for the Bragg geometry, the examined structure works more like a system of coupled resonators that are formed by the flat segments of the 3D structure, whereas for the Laue geometry, the features related to a formation of width SW modes and to the discrete diffraction of the SW were observed.

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