Domain wall motion in ferromagnetically and antiferromagnetically coupled nanowires(Conference Presentation)

demonstrate that the DW velocity can be significantly increased in antiferomagnetically coupled nanowires. The DW velocity increase is related to the exchange fields and reduction or elimination of the magnetostatic effects, which lead to reduction or elimination of the Walker breakdown. In addition, the reduction of the magnetostatic effects results in the reduction of the effects due to the pinning sites and disorder present in most nanomagnetic systems. The reduction of the pinning site and disorder effects further leads to a steadier DW motion. The study includes an analytical model for explaining how and why the Walker breakdown is overcome as well as numerical study supporting the analytical model and providing insights into the effects of the material and structural disorder. The numerical study is based on micromagnetic simulations solving the Landau-Lifshitz-Gilbert equation with continuous spin transfer torque components. The parameter space considered in the models and simulations includes the material properties, various types of disorder, and the exchange coupling in coupled systems. In addition, we discuss various aspects associated with modeling the DW motion in thin nanowires with disorder, including simulation speed, numerical stability, and the simulation model creation.