Recursive evolution of spin-wave multiplets in magnonic crystals of antidot-lattice fractals

Gyuyoung Park,Sang-Koog Kim,Jaehak Yang

doi:10.1038/s41598-021-00417-0

Gyuyoung Park, Sang-Koog Kim + Show 1 more

Open Access

https://doi.org/10.1038/s41598-021-00417-0

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Abstract

We explored spin-wave multiplets excited in a different type of magnonic crystal composed of ferromagnetic antidot-lattice fractals, by means of micromagnetic simulations with a periodic boundary condition. The modeling of antidot-lattice fractals was designed with a series of self-similar antidot-lattices in an integer Hausdorff dimension. As the iteration level increased, multiple splits of the edge and center modes of quantized spin-waves in the antidot-lattices were excited due to the fractals’ inhomogeneous and asymmetric internal magnetic fields. It was found that a recursive development (Fn = Fn−1 + Gn−1) of geometrical fractals gives rise to the same recursive evolution of spin-wave multiplets.

Highlights

We explored spin-wave multiplets excited in a different type of magnonic crystal composed of ferromagnetic antidot-lattice fractals, by means of micromagnetic simulations with a periodic boundary condition
The recursive sequences in fractal growths have barely been studied in ordered spin systems
The proposition of novel magnonic crystals composed of antidot-lattice fractals enlarges a basic understanding of quantized spin-wave modes

Summary

Introduction

We explored spin-wave multiplets excited in a different type of magnonic crystal composed of ferromagnetic antidot-lattice fractals, by means of micromagnetic simulations with a periodic boundary condition. We propose magnonic crystals composed of ferromagnetic antidot-lattice fractals, arranged to one of Sierpiński aperiodic motifs, as studied by micromagnetic simulations along with a delicate analysis of multiplet spin-wave modes. The overlap of scaled antidotlattices in a regular routine yields deterministic fractals, e.g., periodic structures with a local aperiodicity This controllable non-statistical geometry provides a self-similarity in a part of the structure at every magnification, and can be designated according to the Hausdorff dimension of logSN , where S is the scale factor and N is the number of scaled o bjects[31].

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