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NQR study of local structure and cooling rate‐dependent superconductivity in La2CuO4+δ
Journal of Applied Physics (1993)
  • A. P. Reyes, Los Alamos National Laboratory
  • E. T. Ahrens, Los Alamos National Laboratory
  • P. C. Hammel, Los Alamos National Laboratory
  • J. D. Thompson, Los Alamos National Laboratory
  • Paul C. Canfield, Los Alamos National Laboratory
  • Z. Fisk, Los Alamos National Laboratory
  • R. H. Heffner, Los Alamos National Laboratory
  • J. E. Schirber

Preliminary results of structural studies in oxygen‐annealed La2CuO4+δ(δ∼0.03) using 139La nuclear quadrupole resonance (NQR) spectroscopy are reported. Superconducting critical temperatures were found to depend on the rate of cooling through a narrow temperature range near 195 K. Analysis of the 139La NQR spectra reveal that lanthanum atoms in the oxygen‐rich metallic region occupy two sites having different local environments. One site has a structural configuration closely related to the stoichiometric oxygen‐poor compound. The second appears only below 200 K and exhibits a large shift and broad distribution of NQR frequency ν Q . Shifts in ν Q in the vicinity of the superconducting transition were also observed for both metallic sites. Possible origins of these anomalies and their connection to superconductivity are discussed.

  • Superconductivity,
  • Superconducting metals,
  • Atomic spectra,
  • Lanthanum,
  • Quadrupole resonance
Publication Date
Publisher Statement
Copyright 1993 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics 73 (1993): 6323 and may be found at
Citation Information
A. P. Reyes, E. T. Ahrens, P. C. Hammel, J. D. Thompson, et al.. "NQR study of local structure and cooling rate‐dependent superconductivity in La2CuO4+δ" Journal of Applied Physics Vol. 73 Iss. 10 (1993)
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