Transition magnon modes in thin ferromagnetic nanogratings

This work presents micromagnetic simulations in ferromagnetic nanogratings for the full range of directions of an applied in-plane external magnetic field. We focus on the modification of the magnon mode characteristics when the magnetic field orientation is gradually changed between the classical Damon-Eshbach (DE) and backward-volume (BV) geometries. We found that in a specific range of field directions, the magnon mode parameters differ significantly from the parameters in the classical cases, namely, the modes are characterized by complex spatial distributions and have low group velocities. The center of this range corresponds to the direction of the external magnetic field, which gives the maximal nonuniform distribution of the static magnetization in the nanogratings.