Growth of a smooth CaF2 layer on NdFeAsO thin film

11th European Conference on Applied Superconductivity

Sumiya, N.^1 ; Kawaguchi, T.^1,5 ; Chihara, M.^1 ; Tabuchi, M.^2 ; Ujihara, T.^3 ; Ichinose, A.^4 ; Tsukada, I.^4 ; Ikuta, H.^1

Department of Crystalline Materials Science, Nagoya University, Japan^1

Synchrotron Radiation Research Center, Nagoya University, Japan^2

Department of Materials Science and Engineering, Nagoya University, Japan^3

Central Research Institute of Electric Power Industry, Kanagawa, Japan^4

Institut für Festkörperphysik Friedrich, Schiller-Universität Jena, Germany^5

关键词: Barrier layers;    Candidate materials;    High temperature;    Lower temperatures;    NdFeAsO;    Smooth surface;    Superconducting junctions;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/507/1/012047/pdf
DOI  :  10.1088/1742-6596/507/1/012047

来源: IOP

【 摘 要 】

We studied the method to grow a smooth and flat CaF2layer on NdFeAsO thin films since CaF2is a promising candidate material for the barrier layer of a superconducting junction. When the CaF2layer was grown at 800°C, the surface was very rough because {111} facets had grown preferentially. However, when CaF2was grown at lower temperatures and post-annealed in situ at 800°C for 30 min the facets were eliminated and a CaF2layer with a smooth surface was obtained. Fluorine diffusing from CaF2into NdFeAsO was observed when CaF2was grown at high temperatures, but the diffusion was suppressed by lowering the growth temperature to 400°C.