Magneto-optical Kerr effect studies of magnetic micro-structures produced using SIMPA

Using the focused ion beam sputtering capabilities of Scanning Ion Microscope with Polarization Analysis (SIMPA), arrays of regular shaped particles with sizes in the order of 10$\mu$m are produced from a 35nm thick $\rm Ni\sb{83}Fe\sb{17}$ film with in-plane uniaxial anisotropy, The aspect ratio of the particles range from bar-like (50:1) to island-like (1.4:1). Their magnetic properties are studied with longitudinal magneto-optical Kerr effect. Structures with different geometries are found to display fundamental differences in their magnetic behavior. Two types of geometry induced changes in the magnetization reversal process are discerned. These changes are found to agree with a theoretical model based on micromagnetic effects. Light is scattered into a regular diffraction pattern from these structures. The magneto-optical effects in the various spectral orders are examined; they are found to produce similar hysteresis curves as the specular beam