Direct Imaging and Electrical Detection at Room Temperature of a Single Skyrmion

Magnetic skyrmions have excited much interest as the basis for novel data storage applications in which information is encoded and transferred in these magnetic knot-like quasiparticles. The proposed read-out of any such skyrmion-based spintronic device will rely upon the electrical detection of a single magnetic skyrmion within a nanostructure, through, for example, a change in the Hall resistivity. We have fabricated nanodiscs from multilayers of Pt/Co/Ir which can support skyrmions at room temperature and have measured the Hall resistivity whilst simultaneously imaging the spin texture using magnetic scanning transmission x-ray microscopy. We show that the Hall resistivity is correlated to both the presence and size of a magnetic skyrmion in the nanodisc and that the size-dependent part matches the expected anomalous Hall signal when averaging the magnetisation over the disc. The additional contribution arising from the presence of the single skyrmion is 11$\pm$ 1 n{\Omega} cm.