Domain wall displacement in multisegmented nanowires

The precise manipulation of domain walls in nanowires is an essential condition for the realization of memory devices based on domain walls (DWs) displacement. To achieve the controlled movement of the DWs between well-defined positions, a pinning mechanism is needed. An initial approach is to pin the DWs at artificial constrictions in the nanowire and train of such DWs can be displaced regularly. Another approach is to modify locally the material parameters by modulating for example the anisotropy along the wire. In this presentation, we show that using a multisegmented nanowire, the precise manipulation of transverse DWs can be achieved depending on the segments length and materials parameters. The competition between the variation of anisotropy and demagnetizing energy is crucial to obtain the controlled motion. Furthermore, in some cases, the DW displacement with polarity changing can be obtained even with thermal stability just by manipulating the current pulse shape. This paves the way for practical applications with bit encoding in the DWs polarity.