High resolution magnetic force microscopy study of e-beam lithography patterned Co/Pt nanodots

E-beam lithography has been used to pattern a continuous Co/Pt multilayer film with perpendicular anisotropy into circular islands of various sizes down to 25 nm diameter on a 60 nm pitch. High resolution magnetic force microscopy with in situ applied field has been used to directly determine the switching field distribution (SFD) and hysteresis loop of the islands. For the smallest islands, the coercivity is reduced and the width of the SFD is increased, indicating that they would not be well suited to data storage applications.