Discovery of a Novel Iron-based Superconductor Using Low Toxicity Elements

2008.11.05

National Institute for Materials Science
Japan Science and Technology Agency

The National Institute for Materials Science and the Japan Science and Technology Agency recently discovered a new superconductor consisting of only low toxicity elements in Fe-based superconductivity, which is expected to be a new vein of high temperature superconductors.

概要

  1. The National Institute for Materials Science (President: Prof. Teruo Kishi; hereinafter, NIMS) and the Japan Science and Technology Agency (President: Koichi Kitazawa; hereinafter JST) recently discovered a new superconductor consisting of only low toxicity elements in Fe-based superconductivity, which is expected to be a new vein of high temperature superconductors. This achievement was obtained in research by a team led by Dr. Yoshihiko Takano, Group Leader of the Nano Frontier Materials Group of the NIMS Superconducting Materials Center (Managing Director: Hiroaki Kumakura).
  2. At the beginning of 2008, an Fe-based superconductor was discovered by a group under Prof. Hideo Hosono of the Tokyo Institute of Technology. Spurred by this discovery, researchers discovered a succession of new superconductors using similar compounds, suggesting that Fe-based superconductivity is a promising new area for research on high temperature superconductors.The crystal structure which is the origin of superconductivity in conventional high temperature superconductors is a 2-dimensional structure formed by copper and oxygen. In Fe-based superconductivity, the origin of superconductivity is considered to be a 2-dimensional structure formed by iron and arsenic. Therefore, virtually all of the Fe-based superconductors discovered to date have had 2-dimensional structures of iron and arsenic, iron and phosphorus, iron and selenium, etc. However, because arsenic, phosphorus, and selenium are highly toxic elements, for application of Fe-based superconductors, a new superconductor consisting of low-toxicity elements had been desired.
  3. Focusing on iron-tellurium (Te) compounds, which possess a structure similar to that of the Fe-based superconductors but do not display superconductivity, the research group led by Dr. Takano discovered that this material displays superconductivity when doped with a small amount of sulfur (S). Because this Fe-Te-based superconductor FeTe1-xSx does not contain any high-toxicity elements such as arsenic, phosphorus, or selenium, it is considered suitable for application. Efforts to develop superconducting wiring materials and other practical materials using this substance are scheduled for the future.
  4. Potential applications for this discovery include superconducting wiring materials and superconducting devices which enable a current to flow in a state of zero resistance. Because their composition is limited to low-toxicity elements, research and development are easy, and a larger number of researchers are expected to participate in research and development in the future. Thus, this discovery is expected to provide a foothold for the further development of new superconductors.
  5. This research result was obtained as part of the research topic “Elucidation of the Mechanism of Fe-Se-based Superconductors and Search for New Materials” (Research Representative: Yoshihiko Takano) in the research region “Basic Technology of High Temperature Superconductors using New Materials” (Research Supervisor: Prof. Hidetoshi Fukuyama, Department of Physics, Tokyo University of Science) in the JST’s Core Research for Evolutional Science and Technology (CREST) program, and will be announced at the International Symposium on Anomalous Quantum Materials (ISAQM2008) to be held at the University of Tokyo beginning November 7.