Magnetic Force Microscopy of Low-Coercivity Ferromagnetic Nanodiscs

We report the results of magnetic force microscopy (MFM) investigations of low-coercivity Co nanodiscs, with 50 nm lateral size and 20 nm height, fabricated by e-beam lithography and ion etching. We observed two types of MFM contrast in the form of Gaussian and ring distributions caused by strong probe-particle interaction. We compared experimentally the transformation of the MFM contrast from these low-coercivity nanodiscs caused by an external magnetic field applied in situ, and compared the experimental results with theoretical simulations.