Irradiation Effects and Magnetization Reversal in Nanostructures with Perpendicular Anisotropy. Effect of the Dipolar Coupling.

Abstract

  The possibility of modifying solid state properties under ion beam irradiation is a well documented phenomenon. It stands as a very common technique in semiconductor technology. We have used it to design magnetic patterns on ultra-thin films. The local magnetization can be modified without changing such essential characteristics of the films as the perpendicular anisotropy and surface roughness. We report magnetooptical imaging experiments in such magnetically patterned samples: dipolarly coupled dot arrays obtained using a Ga⁺ Focused Ion Beam (FIB) and a comb-like array obtained with a non focused He⁺ ion beam irradiation through a mask fabricated by electron beam lithography.