Spin wave dispersion relation engineering by magnonic crystals with arbitrary symmetry

The use of metasurfaces to engineer the response of magnetic materials is of utmost importance in the field of magnon-spintronics. Here, we demonstrate a method to fabricate one- and two-dimensional magnonic crystals with arbitrary symmetry and use it to engineer the amplitude-frequency characteristic of magnetostatic surface spin waves excited in a magnetic material. The technique is based on the gentle microablation of the sample surface by focused femtosecond laser pulses. Tightly focused illumination allows using modest pulse energy while achieving micrometer precision. By raster scanning the incident laser spot on the sample surface, we control the shape and size of the building blocks constituting the unit cell of the crystal along with its symmetry and lattice parameter. Remarkable and controlled changes in the measured transmission characteristics reveal the strong and complex symmetry-dependent interaction of the spin waves with Bravais and non-Bravais lattices. The described single-step microfabrication method facilitates and speeds up the realization of integrated spintronics components and provides an efficient tool to explore complex magnetic dynamics in scattering lattices.

Automated summary

The use of metasurfaces to engineer the response of magnetic materials is demonstrated in this study. One- and two-dimensional magnonic crystals with arbitrary symmetry are fabricated to engineer the amplitude-frequency characteristic of magnetostatic surface spin waves in a magnetic material. The technique involves the microablation of the sample surface using focused femtosecond laser pulses. Control over the shape, size, symmetry, and lattice parameter of the crystal are achieved by raster scanning the incident laser spot on the sample surface. The interaction of the spin waves with different lattice types is revealed by the measured transmission characteristics.