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Evidence of a Surface to Bulk Core Level Shift in CoFe<sub>2</sub>O<sub>4</sub> Thin Films Grown on Al<sub>2</sub>O<sub>3</sub>

ORAL

Abstract

We find evidence for a surface to bulk core level shift in both the Co 2p and Fe 2p core level photoemission spectra of 5 nm CoFe2O4 (111) film grown on Al2O3 (0001). The Co 2p3/2 and Fe 2p3/2 surface components were distinguished from the bulk components by angle resolved X-ray photoemission spectroscopy (ARXPS). While many complex oxides show a strong preferential surface termination, the surface termination of CoFe2O4 (111) contains both Co and Fe, but the core level photoemission binding energy shifts tend to indicate that the surface is significantly different from the bulk, even for so thin a film. Furthermore, X-ray photoemission spectroscopy (XPS) measurement of 1.5 nm CoFe2O4 (111) film grown on Al2O3 (0001) shows a suboxide interlayer of cobalt. This has implications for cobalt ferrite as a magnetic storage media and could affect growth of this spinel in the degradation of steel in boiling water nuclear power applications.

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Presenters

  • Arjun Subedi

    University of Nebraska - Lincoln

Authors

  • Arjun Subedi

    University of Nebraska - Lincoln

  • Yu Yun

    Physics & Astronomy, University of Nebraska-Lincoln, University of Nebraska - Lincoln

  • Detian Yang

    Physics & Astronomy, University of Nebraska-Lincoln, University of Nebraska - Lincoln

  • Xiaoshan Xu

    Physics & Astronomy, University of Nebraska-Lincoln, Nebraska Center for Materials and Nanoscience and Department of Physics and Astronomy, University of Nebraska - Lincoln, University of Nebraska-Lincoln, University of Nebraska - Lincoln, Department of Physics and Astronomy, University of Nebraska - Lincoln, Physics and Astronomy, University of Nebraska-Lincoln

  • Peter A Dowben

    Physics and Astronomy, University of Nebraska - Lincoln, Department of Physics and Astronomy, University of Nebraska - Lincoln, Department of Physics and Astronomy, University of Nebraska-Lincoln, University of Nebraska - Lincoln