Relationship between superconductivity and crystal structure in NbB 2+x

H. Takagiwa, E. Nishibori, N. Okada, M. Takata, M. Sakata, J. Akimitsu

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

We have performed magnetic susceptibility measurements and precise crystal structure analysis of the nonstoichiometric NbB2+x superconductor to reveal the relationship between Tc and crystal structure. From magnetic susceptibility measurements, it was found that Tc increases from 2.2 to 5.8 K with x. The crystal structures including both chemical compositions and lattice constants were precisely determined by Rietveld refinement using synchrotron X-ray powder diffraction data with three different wavelengths. We found that interatomic Nb-B distance increases with T c. The charge density of NbB2+x was revealed by the maximum entropy method based on Rietveld refinement. We find the difference in the number of electrons in the Nb site and B layer for NbB2+xwith different compositions and Tc.

Original languageEnglish
Pages (from-to)22-25
Number of pages4
JournalScience and Technology of Advanced Materials
Volume7
Issue number1 SPEC. ISS.
DOIs
Publication statusPublished - Jan 2006
Externally publishedYes

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Keywords

  • Maximum Entropy Method (MEM)
  • NbB
  • Superconductivity

ASJC Scopus subject areas

  • Materials Science(all)

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