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Title: Nanoscale coherent intergrowthlike defects in a crystal of La1.9Ca1.1Cu2O6+δ made superconducting by high-pressure oxygen annealing

Superconductivity with Tc = 53.5 K has been induced in a large La₁.₉Ca₁.₁Cu₂O₆ (La-2126) single crystal by annealing in a high partial-pressure of oxygen at 1200°C. Using transmission electron microscopy (TEM) techniques, we show that a secondary Ca-doped La₂CuO₄ (La-214) phase, not present in the as-grown crystal, appears as a coherent “intergrowth” as a consequence of the annealing. A corresponding secondary superconducting transition near 13 K is evident in the magnetization measurement. In this study, electron energy loss spectroscopy (EELS) reveals a pre-edge peak at the O K edge in the superconducting La-2126 phase, which is absent in the as-grown crystal, confirming the hole-doping by interstitial oxygen.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [2]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States); Columbia Univ., New York, NY (United States)
Publication Date:
OSTI Identifier:
1182488
Report Number(s):
BNL--107343-2015-JA
Journal ID: ISSN 1098-0121; PRBMDO; R&D Project: MA015MACA; PO010; KC0201010; KC0201060
Grant/Contract Number:
SC00112704
Type:
Accepted Manuscript
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 90; Journal Issue: 13; Journal ID: ISSN 1098-0121
Publisher:
American Physical Society (APS)
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY