Bright and dark spin-wave solitons in ultra-thin iron garnet nanostripes

Based on simulations, we discuss the potential of micromagnetic models of ferrimagnetic iron garnets (YIG and GdIG) to describe the propagation of bright and dark spin-wave solitons in ultra-thin nanostripes (of 10 nm thickness) with perpendicular magnetic anisotropy. We formulate a macroscopic model of nanostripes of two-sublattice ferrimagnets driven with a local field from an antenna. Propagating bright and dark spin-wave pulses are created by applying a pulsed field. The stability of their propagation and their stability against collisions (the soliton property) are verified. The latter process is driven by two antennas attached at both ends of the nanostripe. For YIG, the soliton properties of generated bright and dark pulses are confirmed in the simulations; however, they are not for the material parameters of GdIG near the compensation point (at room temperature). Instead, the simulations show breaking the continuous waves up into an aperiodic series of low-length excitations, which is characteristic of the effect of modulational instability and the finding is supported by the linear stability analysis.