Tuning of spin-wave transmission and mode conversion in microscopic YIG waveguides with magnonic crystals

We report experimental results on spin-wave propagation, transmission gap tuning, and mode conversion in straight, curved, and Y-shaped yttrium iron garnet waveguides with magnonic crystals made of submicrometer-wide airgrooves. We observe forbidden frequency gaps with sizes up to 200 MHz in straight waveguides and narrowing of the gaps in curved and Y-shaped waveguides. The spin-wave transmission signal is strongly suppressed inside the gaps and remains high at allowed frequencies for all waveguide types. Using super-Nyquist sampling magneto-optical Kerr effect microscopy, we image symmetric and asymmetric spin-wave interference patterns, the self-focusing of propagating spin waves, and interconversions between width modes with different quantization numbers. Published under an exclusive license by AIP Publishing.

Automated summary

This study reports experimental results on spin-wave propagation, transmission gap tuning, and mode conversion in straight, curved, and Y-shaped yttrium iron garnet waveguides with submicrometer-wide airgrooves. The study observes forbidden frequency gaps in straight waveguides and narrowing of the gaps in curved and Y-shaped waveguides. The findings show that the spin-wave transmission signal is strongly suppressed inside the gaps and remains high at allowed frequencies for all waveguide types.