Berlin 2018 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 17: Poster Session I

DS 17.45: Poster

Dienstag, 13. März 2018, 18:15–20:15, Poster B

Ni_xO thin films - impact of composition x on optical parameters — •Martin Becker, Fabian Michel, Angelika Polity, and Peter J. Klar — Institute for Exp. Physics I and Center for Materials Research (LaMa), Justus Liebig University Giessen, Germany

Ni_xO thin films were grown on single crystal sapphire substrates of various orientation by ion beam sputtering of a Ni metal target in a mixed argon and oxygen atmosphere. Epitaxial growth was verified by X-ray diffraction measurements on all substrates. Surface morphology and surface roughness were explored via atomic force microscopy. Consequential, Ni_xO films on c-plane and a-plane sapphire were found to be best suited to serve as antiferromagnetic pinning layers.
For thin films grown on c-plane sapphire the composition of the film was varied systematically by changing the ratio of inert gas (Ar) and reactive gas (O₂). The information of chemical bonding was investigated via X-ray photoelectron spectroscopy. Optical characterization yielded a strong dependence of the refractive index and the optical band gap of Ni_xO on composition x, although the samples were very similar relating to their structure. The dependence of the refractive index of Ni_xO on composition x contributes substantially to the broad span of values reported for Ni_xO in literature.