In magnetic nanowires with perpendicular magnetic anisotropy (PMA) magnetic domain walls (DW) are narrow and can move rapidly driven by current induced torques. This enables important applications like high-density memories for which the precise detection of the position and motion of a propagating DW is of utmost interest. Today's DW detection tools are often limited in resolution, or acquisition speed, or can only be applied on specific materials. Here, we show that the anomalous Nernst effect provides a simple and powerful tool to precisely track the position and motion of a single DW propagating in a PMA nanowire. We detect field and current driven DW propagation in both metallic heterostructures and dilute magnetic semiconductors over a broad temperature range. The demonstrated spatial resolution below 20 nm is comparable to the DW width in typical metallic PMA systems.

26 pages including supplementary information