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Title: Structural feature controlling superconductivity in compressed BaFe{sub 2}As{sub 2}

Superconductivity can be induced with the application of pressure but it disappears eventually upon heavy compression in the iron-based parent compound BaFe{sub 2}As{sub 2}. Structural evolution with pressure is used to understand this behavior. By performing synchrotron X-ray powder diffraction measurements with diamond anvil cells up to 26.1 GPa, we find an anomalous behavior of the lattice parameter with a S shape along the a axis but a monotonic decrease in the c-axis lattice parameter with increasing pressure. The close relationship between the axial ratio c/a and the superconducting transition temperature T{sub c} is established for this parent compound. The c/a ratio is suggested to be a measure of the spin fluctuation strength. The reduction of T{sub c} with the further increase of pressure is a result of the pressure-driven weakness of the spin-fluctuation strength in this material.
Authors:
 [1] ;  [2] ;  [3] ;  [1] ;  [4] ; ;  [5] ;  [1] ;  [4] ;  [2]
  1. Center for High Pressure Science and Technology Advanced Research, Shanghai 201203 (China)
  2. (United States)
  3. Key Laboratory of Materials Physics and Center for Energy Matter in Extreme Environments, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China)
  4. (China)
  5. Department of Physics, Zhejiang University, Hangzhou 310027 (China)
Publication Date:
OSTI Identifier:
22277971
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 8; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; AXIAL RATIO; BARIUM COMPOUNDS; COMPRESSION; CRYSTAL STRUCTURE; DIAMONDS; FLUCTUATIONS; IRON ARSENIDES; LATTICE PARAMETERS; PRESSURE DEPENDENCE; SPIN; SUPERCONDUCTIVITY; TRANSITION TEMPERATURE; X-RAY DIFFRACTION