Magnetic field induced spin wave reflection by a domain wall in synthetic antiferromagnets

Abstract

Micromagnetic simulations are used to investigate the effect of an external magnetic field on the interaction between domain walls and linearly polarized propagating spin waves in synthetic antiferromagnets. Two regimes with a sharp transition between them are found. At large fields, spin waves are strongly reflected by the domain wall and, consequently, the latter is propelled forward. At low fields, however, there is no reflection and yet the domain wall undergoes a small forward displacement, which is attributed to the change in linear momentum of the magnons as they pass through the domain wall and to the imbalance in the population of the two oscillation modes present in the linearly polarized excitation. The transition between the two regimes occurs at the field value for which the excitation frequency falls below the threshold of the high-frequency mode.