Tokyo University of Science team inverse-designs 2D magnonic crystals with wider band gaps

A Tokyo University of Science team led by Professor Masato Kotsugi and doctoral student Ryunosuke Nagaoka demonstrated an inverse-design framework for two-dimensional magnonic crystals aimed at wider complete magnonic band gaps, phys.org reported. Findings were published in Small Structures on July 28, 2026. Magnonic crystals are engineered magnetic materials with periodic structures that control spin-wave, or magnon, propagation, analogous to how semiconductor crystals guide electrons. Magnonic band gaps are frequency ranges where spin waves cannot propagate and are central design targets, but geometry-to-dispersion links are complex and higher-order bands are hard to control. The researchers combined frequency-domain micromagnetic simulations based on the frequency-domain Landau-Lifshitz-Gilbert equation with a genetic algorithm for global optimization, defining the widest complete magnonic band gap as the objective. Kotsugi said inverse design expands the design space toward unconventional lattices with large gaps. The work targets applications that use magnons as information carriers in logic, memory and physical neural networks.