Microstructure and flux distribution in both pure and carbon-nanotube-embedded Bi2Sr2CaCu2O8+δ superconductors

Sun Li Huang, M. R. Koblischka, K. Fossheim, T. W. Ebbesen, T. H. Johansen

研究成果: Article査読

31 被引用数 (Scopus)


In order to improve pinning properties of bulk Bi2Sr2CaCu2O8+δ (Bi-2212) materials, samples of both pure Bi-2212 and Bi-2212 with carbon nanotubes embedded (CNTE Bi-2212) have been prepared by partial-melting processing. The preparation conditions are chosen so that a significant fraction of carbon nanotubes can be successfully embedded in the material, as indicated by thermogravimetric analysis. The micro structure and composition of non-superconducting second phases are found to be different in these two types of samples. By means of magneto-optical (MO) imaging, flux distributions in both types of samples are investigated up to T= 77 K. The MO investigation reveals the propagation of a flux front in both pure and CNTE Bi-2212, showing that there is a strong coupling between grains (clusters) which enables the flow of inter-granular currents. This grain coupling persists in our field range of ±180 mT. In bulk non-textured ceramic high-Tc superconductors, the flux fronts caused by currents flowing through the entire sample are observed for the first time. Intra-granular current densities are obtained from the images as a function of grain size. The MO investigations have revealed the differences in the current densities caused by the presence of carbon nanotubes, showing that the carbon nanotubes are indeed functioning like columnar defects produced by heavy-ion irradiation. The increase of the flux penetration field is also a manifestation of the increase of the transport current density in the CNTE Bi-2212. The superconducting properties in our samples are very well reproducible.

ジャーナルPhysica C: Superconductivity and its applications
出版ステータスPublished - 1999

ASJC Scopus subject areas

  • 電子材料、光学材料、および磁性材料
  • 凝縮系物理学
  • エネルギー工学および電力技術
  • 電子工学および電気工学


「Microstructure and flux distribution in both pure and carbon-nanotube-embedded Bi2Sr2CaCu2O8+δ superconductors」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。