Ferromagnetism in post-annealed sputtered Cr-doped In2O3 thin films

Authors

  • Yassine Ait-El-Aoud,

    1. Department of Electrical and Computer Engineering, Center for Electromagnetic Materials and Optical Systems, University of Massachusetts, Lowell, Massachusetts, USA
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  • Mark C. Hickey,

    1. Department of Electrical and Computer Engineering, Center for Electromagnetic Materials and Optical Systems, University of Massachusetts, Lowell, Massachusetts, USA
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  • Adil-Gerai Kussow,

    1. Department of Physics, University of Massachusetts, Lowell, Massachusetts, USA
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  • Alkim Akyurtlu

    Corresponding author
    1. Department of Electrical and Computer Engineering, Center for Electromagnetic Materials and Optical Systems, University of Massachusetts, Lowell, Massachusetts, USA
    • Corresponding author: e-mail alkim_akyurtlu@uml.edu, Phone: +1 978 934 3336, Fax: +1 978 934 3027, Web: faculty.uml.edu/aakyurtlu

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Abstract

In the present work, we have studied the effect of a post-annealing process on the magnetic properties of thin films of Cr-doped indium oxide, In2−xCrxO3−δ. Samples with low stoichiometric oxygen deficiency, δ, which is required for ferromagnetic behavior, were fabricated using a DC/RF magnetron sputtering method. The post-annealing process described in this paper allows control of the oxygen deficiency. This method has led to samples which show clear ferromagnetic behavior at both low temperatures and at room temperature with saturation magnetic moments up to ∼1.5 µB/Cr-atoms. The measured high Curie temperature, TC ∼ 740 K, justifies the indirect electron-mediated ferromagnetic coupling of the spins of Cr ions. The ferromagnetic coupling was found to be mostly a bulk effect, which is not affected by the surface of the film.

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