Abstract
The effects of heat treatment on room temperature ferromagnetism of Co-doped ZnO were investigated with a (ZnO 20Å/Co x Å)20 multilayer structure where x = 1.5, 3, 4.3, 6 and 9 Å. As the thickness of the Co sub-layer increased, the ZnO/Co multilayer changed its magnetic state from diamagnetism at Co 1.5 Å and 3 Å to weak ferromagnetism at Co 4.3 Å and strong ferromagnetism at Co 6 Å and 9 Å. The heat treatment, in a vacuum at 400°C, changed the diamagnetic property into a ferromagnetic one, resulting in room temperature ferromagnetism for all Co sub-layer thicknesses. The improvement in ferromagnetism could be ascribed to the exchange coupling between dispersed Co atoms through XRD, optical transmittance and TEM analysis.
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Kang, Sg., Kim, Y., Kim, S.E. et al. The effects of heat treatment on room temperature ferromagnetism in a digitally Co doped ZnO thin film. Electron. Mater. Lett. 9, 7–11 (2013). https://doi.org/10.1007/s13391-012-1094-2
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DOI: https://doi.org/10.1007/s13391-012-1094-2