Field operating window of nanodevices employing the domain wall propagation through the stripes intersection: Numerical optimization

In this paper, we present the detailed numerical study of domain wall (DW) dynamics in thin magnetic stripes and in nanostructures containing intersections of such stripes. We focus on the DW propagation through these intersections (crosses), because these are the key elements in field-based multiturn sensors and magnetic logic devices. The DW propagation through such intersections is the main problem by ensuring the functional reliability of the abovementioned devices due to (i) the strong pinning of a DW at these crosses and (ii) the risk that a wrong cross “shoulder” is reversed by the DW propagation. By means of micromagnetic simulations, the operating field range for the desired DW propagation in devices with a constant stripe width is determined, and the drawbacks of this simple design are discussed. To overcome these drawbacks, we suggest a new design employing the stripes with a modulated width. We show that sensors with this design are expected to have a higher reliability and that their field operating window can be controlled in a more flexible way.