Nano-patterned magnonic crystals based on ultrathin YIG films

TL;DR

This paper presents the fabrication and detailed analysis of nano-patterned magnonic crystals using ultrathin YIG films, revealing complex spin wave behaviors and attenuation characteristics near the band gap edges.

Contribution

It introduces a novel nano-patterned magnonic crystal based on 20 nm YIG films and provides detailed phase-resolved measurements of spin wave dispersion and attenuation.

Findings

Maximum attenuation occurs near the magnonic band gap edge.

Spin wave propagation is influenced by non-uniform field potentials.

Detailed dispersion and attenuation maps of spin waves in the crystal.

Abstract

We demonstrate a microscopic magnonic-crystal waveguide produced by nano-patterning of a 20 nm thick film of Yttrium Iron Garnet. By using the phase-resolved micro-focus Brillouin light scattering spectroscopy, we map the intensity and the phase of spin waves propagating in such a periodic magnetic structure. Based on these maps, we obtain the dispersion and the attenuation characteristics of spin waves providing detailed information about the physics of spin-wave propagation in the magnonic crystal. We show that, in contrast to the simplified physical picture, the maximum attenuation of spin waves is achieved close to the edge of the magnonic band gap, which is associated with non-trivial reflection characteristics of spin waves in non-uniform field potentials.