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Title: Synthesis, characterization, phase diagrams and superconducting and normal state magnetic properties of La2-xSrxCuO4 (0 ≤ x ≤ 0.08) and electrochemically oxidized La2-xSrxCuO4+δ (0 ≤ x ≤ 0.33, 0 ≤ δ ≤ 0.12)

Abstract

La2-xSrxCuO4 (0 ≤ x ≤ 0.15) can all be intercalated with oxygen by a novel electrochemical oxidation method. Bulk superconductivity is found with an onset Tc~ 40 K for the whole range 0.01 ≤ x ≤ 0.15; for x = 0.25 and 0.33, the electrochemical oxidation did not improve the superconducting properties. The magnetic susceptibility χ(T = 50--320 K) data for La2CuO4.11 and La1.92Sr0.08CuO4.07 are nearly identical with those of conventionally prepared La1.85Sr0.15CuO4, indicating that the hole doping level (p) in the CuO2 planes of the three compounds is nearly the same. Combined thermogravimetric analysis and iodometric titration experiments indicate that part of the intercalated oxygen has a formal valence close to -1. The maximum doped-hole concentration in the CuO2 planes that can be achieved from combined Sr-doping and electrochemical oxygen doping for 0 ≤ x ≤ 0.15 is p ~ 0.16 holes/formula unit. Oxygen can also intercalate into single crystal La2CuO4 through a slow electrochemical oxidation process. The required low current and long time for the charging process reflects that the oxygen intercalation for a single crystal is limited by its small specific surface area and long diffusion distance. The anisotropic superconducting, magnetic and transport properties are summarized andmore » compared with those of polycrystalline La2CuO4+δ as well as of YBa2Cu3O7-δ and La2-xSrxCuO4 single crystals. The single crystal La2CuO4+δ has a maximum Tc ~ 40 K, which is lower than that (Tc ~ 42--45) of the corresponding polycrystalline samples. The magnetic phase diagram of La2-xSrxCuO4 in the antiferromagnetic (AF) regime (0 ≤ x ≤ 0.02) has been derived from 139La NQR studies from 4 to 250 K.« less

Authors:
 [1]
  1. Iowa State Univ., Ames, IA (United States)
Publication Date:
Research Org.:
Ames Lab., Ames, IA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
140410
Report Number(s):
IS-T-1661
ON: DE94005260; TRN: 94:014805
DOE Contract Number:  
W-7405-ENG-82
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: TH: Thesis; PBD: Aug 1993
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; LANTHANUM OXIDES; MAGNETIC PROPERTIES; PHASE DIAGRAMS; SYNTHESIS; STRONTIUM OXIDES; COPPER OXIDES; HIGH-TC SUPERCONDUCTORS

Citation Formats

Chou, Fangcheng. Synthesis, characterization, phase diagrams and superconducting and normal state magnetic properties of La2-xSrxCuO4 (0 ≤ x ≤ 0.08) and electrochemically oxidized La2-xSrxCuO4+δ (0 ≤ x ≤ 0.33, 0 ≤ δ ≤ 0.12). United States: N. p., 1993. Web. doi:10.2172/140410.
Chou, Fangcheng. Synthesis, characterization, phase diagrams and superconducting and normal state magnetic properties of La2-xSrxCuO4 (0 ≤ x ≤ 0.08) and electrochemically oxidized La2-xSrxCuO4+δ (0 ≤ x ≤ 0.33, 0 ≤ δ ≤ 0.12). United States. https://doi.org/10.2172/140410
Chou, Fangcheng. 1993. "Synthesis, characterization, phase diagrams and superconducting and normal state magnetic properties of La2-xSrxCuO4 (0 ≤ x ≤ 0.08) and electrochemically oxidized La2-xSrxCuO4+δ (0 ≤ x ≤ 0.33, 0 ≤ δ ≤ 0.12)". United States. https://doi.org/10.2172/140410. https://www.osti.gov/servlets/purl/140410.
@article{osti_140410,
title = {Synthesis, characterization, phase diagrams and superconducting and normal state magnetic properties of La2-xSrxCuO4 (0 ≤ x ≤ 0.08) and electrochemically oxidized La2-xSrxCuO4+δ (0 ≤ x ≤ 0.33, 0 ≤ δ ≤ 0.12)},
author = {Chou, Fangcheng},
abstractNote = {La2-xSrxCuO4 (0 ≤ x ≤ 0.15) can all be intercalated with oxygen by a novel electrochemical oxidation method. Bulk superconductivity is found with an onset Tc~ 40 K for the whole range 0.01 ≤ x ≤ 0.15; for x = 0.25 and 0.33, the electrochemical oxidation did not improve the superconducting properties. The magnetic susceptibility χ(T = 50--320 K) data for La2CuO4.11 and La1.92Sr0.08CuO4.07 are nearly identical with those of conventionally prepared La1.85Sr0.15CuO4, indicating that the hole doping level (p) in the CuO2 planes of the three compounds is nearly the same. Combined thermogravimetric analysis and iodometric titration experiments indicate that part of the intercalated oxygen has a formal valence close to -1. The maximum doped-hole concentration in the CuO2 planes that can be achieved from combined Sr-doping and electrochemical oxygen doping for 0 ≤ x ≤ 0.15 is p ~ 0.16 holes/formula unit. Oxygen can also intercalate into single crystal La2CuO4 through a slow electrochemical oxidation process. The required low current and long time for the charging process reflects that the oxygen intercalation for a single crystal is limited by its small specific surface area and long diffusion distance. The anisotropic superconducting, magnetic and transport properties are summarized and compared with those of polycrystalline La2CuO4+δ as well as of YBa2Cu3O7-δ and La2-xSrxCuO4 single crystals. The single crystal La2CuO4+δ has a maximum Tc ~ 40 K, which is lower than that (Tc ~ 42--45) of the corresponding polycrystalline samples. The magnetic phase diagram of La2-xSrxCuO4 in the antiferromagnetic (AF) regime (0 ≤ x ≤ 0.02) has been derived from 139La NQR studies from 4 to 250 K.},
doi = {10.2172/140410},
url = {https://www.osti.gov/biblio/140410}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Aug 01 00:00:00 EDT 1993},
month = {Sun Aug 01 00:00:00 EDT 1993}
}

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