Electric-Field Control of Magnon Gaps in a Ferromagnet using a Spatially-Periodic Electric Field

The frequencies and linewidths of spin waves in one-dimensional (1D) and two-dimensional (2D) periodic superlattices of magnetic materials are found, using the Landau–Lifshitz–Gilbert equations. The form of the exchange field from a surface-torque-free boundary between magnetic materials is derived, and magnetic-material combinations are identified which produce gaps in the magnonic spectrum across the entire superlattice Brillouin zone for hexagonal and square-symmetry superlattices. The magnon gaps and spin-wave dispersion properties of a uniform magnetic material under the influence of a periodic electric field are presented. Such results suggest the utility of magnetic insulators for electric-field control of spin-wave propagation properties.