Embodiments relate to xMR sensors having very high shape anisotropy. Embodiments also relate to novel structuring processes of xMR stacks to achieve very high shape anisotropies without chemically affecting the performance relevant magnetic field sensitive layer system while also providing comparatively uniform structure widths over a wafer, down to about 100 nm in embodiments. Embodiments can also provide xMR stacks having side walls of the performance relevant free layer system that are smooth and/or of a defined lateral geometry which is important for achieving a homogeneous magnetic behavior over the wafer.