Nanoscale physics

Theoretical study of nonlinear spin waves in magnetic multilayers with metasurfaces
Gerasimchuk V.S.1, Gerasimchuk I.V.1,2
1 Faculty of Physics and Mathematics, National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Peremohy Ave. 37, Kyiv 03056, Ukraine
2 Department of Physics of Meso- and Nanocrystal Magnetic Structures, Institute of Magnetism, Natl. Acad. Sci. Ukraine and Min. Edu. Sci. Ukraine, Akad. Vernadsky Blvd. 36-b, Kyiv 03142, Ukraine
E-mail: igor.gera@gmail.com

The multilayer magnetic structures are widely investigated regarding their potential technological applications. Recently, magnetic film micro- and nanostructures have been intensively studied as possible candidates for the creation of promising devices for spintronics and magnonics. Of particular interest are multilayer periodic structures with magnetic ordering which have pronounced anisotropic properties. In turn, the presence of metasurfaces (thin layers) in layered structures with different magnetic properties and different ratios of layer thicknesses is the requirement for the formation of spin-wave excitations localized at the metasurfaces between the contacting magnetic layers [1]. Earlier, the analysis of such excitations was limited to linear on the oscillation amplitude approximation, but now the study of nonlinear spin-wave excitations and their properties become actual. Due to the new technological possibilities of the creating of periodic nanostructures, the investigations of the propagation of nonlinear spin waves localized near thin layers of the magnetic material in a system of thin plane parallel magnetic layers (plane magnetic defects) are of great practical interest. 
In the present work, we study analytically the localization of nonlinear waves propagating in a five-layer magnetic structure along the alternating wide and thin layers with different single-ion anisotropies in them. We find the exact solutions for spin wave localized states, the total number of elementary excitations localized in the system and its total energy as functions of the scaling variable characterizing the distance between the plane magnetic defects. We present all these dependences in the universal scaling forms valid for different values of the characteristic of magnetic defects. 

1.	Gerasimchuk I. V., Gerasimchuk V. S. Localization of Nonlinear Spin Waves in Magnetic Multilayers // J. Appl. Phys.-2018.-124, No.8.-P. 085301.