Studies of Ni and Co Doped Amorphous AlN for Magneto-optical Applications

Abstract

AbstractMagneto-optical properties of Ni- and Co-doped amorphous AlN thin films were investigated as a function of post grown annealing temperature using magneto-optical Kerr effect (MOKE) spectroscopy. The x-ray diffraction spectra confirmed that the as-grown material is amorphous and retained its morphology after thermal treatment; however the sample morphology strongly depends on the concentration of incorporated transition metals. We observed with help of transmission electron microscopy and atomic force microscopy that the films surface containing TMs with concentrations larger than ∼10 at.% undergo morphological changes suggesting possible Ni and Co atom clustering. Significant enhancement of the polar Kerr rotation signal was observed for Ni- and Co-doped a-AlN materials annealed above 300 °C in nitrogen. The studied materials have shown strong magnetic isotropy in polar geometry whereas the MOKE measurements in longitudinal geometry did not show an explicit signal for the transition metals doped a-AlN studied.