Materials Science and Engineering, working in the research group of Amal El-Ghazaly. As a KIC graduate fellow, Yulan will work to image the spin textures of high MS NPs to determine the size range where the single-domain state can be achieved. In collaboration with the Muller group, the Fe-Co NPs of various size will be imaged using the new microscope with the smaller probe and in conjunction with the ptychography information. Subsequent analysis will be used to validate our simulation- and experimentally-informed hypotheses of the four main magnetization regimes of Fe-Co NPs as a function of sizes around the single-domain limit. These results will, for the first time, visually reveal the predicted spin textures at the nanoscale.