Nanostructure characterization of Ni and B layers as artificial pinning centers in multilayered MgB2/Ni and MgB2/B superconducting thin films

H. Sosiati, S. Hata, T. Doi, A. Matsumoto, H. Kitaguchi, H. Nakashima

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4 Citations (Scopus)


Research on the MgB2/Ni and MgB2/B multilayer films fabricated by an electron beam (EB) evaporation technique have been extensively carried out. The critical current density, Jc of MgB2/Ni and MgB2/B multilayer films in parallel fields has been suggested to be higher than that of monolayer MgB2 film due to introducing the artificial pinning centers of nano-sized Ni and B layers. Nanostructure characterization of the artificial pinning centers in the multilayer films were examined by transmission electron microscopy (TEM) and scanning TEM (STEM-energy dispersive X-ray spectroscopy (STEM-EDS))-EDS to understand the mechanism of flux pinning. The growth of columnar MgB2 grains along the film-thickness direction was recognized in the MgB2/Ni multilayer film, but not in the MgB2/B multilayer film. Nano-sized Ni layers were present as crystalline epitaxial layers which is interpreted that Ni atoms might be incorporated into the MgB2 lattice to form (Mg,Ni)B 2 phase. On the other hand, nano-sized B layers were amorphous layers. Crystalline (Mg,Ni)B2 layers worked more effectively than amorphous B-layers, providing higher flux-pinning force that resulted in higher Jc of the MgB2/Ni multilayer film than the MgB 2/B multilayer film.

Original languageEnglish
Pages (from-to)1-8
Number of pages8
JournalPhysica C: Superconductivity and its applications
Publication statusPublished - May 15 2013

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


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