Creating and imaging nanosized magnets using HIM and TEM holography

Besides imaging, gas field ion source (GFIS) based microscopes [1] are used for materials modification. This usually is based on the use of high fluence to either mill the sample material or implant Nobel gas ions into the target material [2]. Here, we present a novel route utilizing a Helium Ion Microscope (HIM) to form nano–sized magnets of arbitrary shape using very low fluences (6 × 1014 cm−2) of 20 keV–25 keV Neon ions. The fine Neon beam available in the HIM is used to locally switch 40nm thin Fe60Al40 films from the well ordered paramagnetic B2 structure into the ferromagnetic A2 structure [3, 4]. Planar structures potentially useful for applications such as spin valves or other spin–transport devices have been formed this way. Kerr Microscopy and off–axis TEM holography has been used to analyze the resulting magnetic nano–structures. Results on the energy depended depth of magnetization as well as on the lateral definition of the magnetic structures due to scattering are presented.