Annealing-induced Fe oxide nanostructures on GaAs

We report the evolution of Fe oxide nanostructures on GaAs(100) upon preand post-growth annealing conditions. GaAs nanoscale pyramids were formed on the GaAs surface due to wet etching and thermal annealing. An 8.0-nm epitaxial Fe film was grown, oxidized, and annealed using a gradient temperature method. During the process the nanostripes were formed, and the evolution has been demonstrated using transmission and reflection high energy electron diffraction, and scanning electron microscopy. These nanostripes exhibited uniaxial magnetic anisotropy. The formation of these nanostructures is attributed to surface anisotropy, which in addition could explain the observed uniaxial magnetic anisotropy.