Fabrication, investigation and modification of magnetic states in nano-scale patterned cobalt films by using scanning ion microscopy with polarization analysis (SIMPA)

Focused ion beam (FIB) lithography is used to fabricate patterned Co nano-elements from ultra-thin (30 nm thick), electron-beam-evaporated Co films. The spin- and spatially-resolved surface magnetic structure (SMS) of the nano-scale Co elements is imaged in situ by using scanning ion microscopy with polarization analysis (SIMPA). SIMPA spin maps directly reveal the detailed spin structure of magnetic vortex and antivortex states, which can be utilized for ultra-high density, non-volatile magnetic memory devices. It is found that the SMS of the nano-magnetic structures depends strongly on the size of the patterned Co elements. In addition, FIB etching is utilized in situ to create well-defined defects (antidots) in the patterned Co elements, which strongly modify the previously existing SMSs leading to novel nano-magnetic states. The results show that ion-surface interaction, as provided by SIMPA spin mapping and in situ FIB processing, can be profitably exploited for studying SMSs of patterned magnetic systems to be used for nano-scale magnetic memory and magnetic logic devices.