Structural characterization of magnetic nanostripes by fast domain wall injection

The process of injection of a magnetic domain wall (DW) by means of a 25-100 ns current pulse flowing through an adjacent conductive track has been studied in detail. We find that the probability of creating a DW through this method is 100% for a wide range of amplitudes of the current pulse and of the external magnetic field, including zero external magnetic field. Micromagnetic simulations show that the DW is created in the first nanosecond of the pulse, and its movement is strongly influenced by the induced Oersted field, which can reach considerable values, especially in the perpendicular-to-plane direction. The edge roughness and temperature play also a crucial role in determining the type of DW that travels through the wire. Experimentally we show that a map of the probability of injection of a DW by a current pulse can be a very powerful method to check the structural quality of the nanostripe, which has very important practical consequences for research in this area.