Imaging the Interaction of Electrical Currents with Magnetization Distributions

About a decade ago, the understanding of the interaction mechanisms between electrical currents and magnetic objects like domain walls or vortices was still in its infancy. Both, theory and experiments were moving on uncharted grounds, with new and many times contradicting results being published from different groups at increasing pace. Previously, only the Oersted field from a current was available to manipulate the magnetic state of a system. The latter was extensively used in magnetic storage devices, starting from the early core memory up to the write heads of the latest hard drive technologies based on perpendicular recording and tunnel-magnetoresistive (TMR) readout sensors, to alter the state of the magnetic bits. Even early prototypes of magnetic random-access memory (MRAM) used the Oersted field for writing.