Magnonics is a budding research field in nanomagnetism and nanoscience that addresses the use of spin waves (magnons) to transmit, store, and process information. The rapid advancements of this field during last one decade in terms of upsurge in research papers, review articles, citations, proposals of devices as well as introduction of new sub-topics prompted us to present the first roadmap on magnonics. This is a collection of 22 sections written by leading experts in this field who review and discuss the current status besides presenting their vision of future perspectives. Today, the principal challenges in applied magnonics are the excitation of sub-100 nm wavelength magnons, their manipulation on the nanoscale and the creation of sub-micrometre devices using low-Gilbert damping magnetic materials and its interconnections to standard electronics. To this end, magnonics offers lower energy consumption, easier integrability and compatibility with CMOS structure, reprogrammability, shorter wavelength, smaller device features, anisotropic properties, negative group velocity, non-reciprocity and efficient tunability by various external stimuli to name a few. Hence, despite being a young research field, magnonics has come a long way since its early inception. This roadmap asserts a milestone for future emerging research directions in magnonics, and hopefully, it will inspire a series of exciting new articles on the same topic in the coming years.

We observe and explain theoretically strain-induced spin-wave routing in the bilateral composite multilayer. By means of Brillouin light scattering and microwave spectroscopy, we study the spin-wave transport across three adjacent magnonic stripes, which are strain coupled to a piezoelectric layer. The strain may effectively induce voltage-controlled dipolar spin-wave interactions. We experimentally demonstrate the basic features of the voltage-controlled spin-wave switching. We show that the spin-wave characteristics can be tuned with an electrical field due to piezoelectricity and magnetostriction of the piezolayer and layered composite and mechanical coupling between them. Our experimental observations agree with numerical calculations.

We experimentally study the spin-wave coupling in adjacent ferrimagnetic-ferroelectric heterostructures. By using the space-resolved Brillouin light-scattering spectroscopy, we perform a systematic study of the coupling of waves propagating in both a magnetic and a ferroelectric layer. We demonstrate the voltage-controlled transfer of the spin-wave energy between the adjacent bilayers. Our results show, that the coupling efficiency of the proposed laterally coupled multiferroics can be tuned by independent variation of the applied magnetic and electric field, which opens exciting prospects for an emerging field of magnonics.

We report experimental investigation of spin-wave transport along combined magnonic structures which are comprised of the $90°$ -magnonic bend and adjacent nonidentical magnetic stripes. The latter has the form of a spin-wave coupler. Using space-resolved Brillouin light-scattering spectroscopy and micromagnetic simulations, we study propagation, transformation, and coupling of spin waves in the combined structure. We show that characteristics of spin-wave transport in such structures are defined strongly by the intermodal dipolar spin-wave coupling. The developed structure can operate as a multifunctional magnonic device and can be used to turn the spin wave at $90°$ performing the functionality of a directional coupler, a power splitter, a multiplexer, or a frequency separator. Our results show that interconnection of magnonic units can be utilized for further development of planar topologies of insulator-based magnonic networks.

The spin-wave dynamics in the system of lateral magnetic microstructures have been studied experimentally and numerically. Regimes of the propagation of coupled spin waves have been investigated by...

Features of the propagation of magnetostatic waves in a tangentially magnetized magnonic crystal structure based on iron–yttrium garnet with a two-dimensional array of grooves on the surface are studied. Numerical simulation is performed by the finite element method and the dispersion characteristics and the spatial distribution of fields of eigenmodes of surface magnetostatic waves propagating in this structure are calculated. The characteristics of waves in the magnonic crystal structure are experimentally studied by means of Brillouin scattering. It is shown that the formation of waveguide channels is possible when the frequency of the input signal is close to the frequency of the band gap of the structure.