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Title: Solid state chemistry of new perovskite and Ruddlesden-Popper phases in the La{sub 2}O{sub 3}-CaO-CuO system at high pressures

Abstract

The crystal chemistry of the system LaO{sub 1.5}-CaO-CuO at the 1:1:2 composition was studied at high pressures with the goal of stabilizing new perovskite cuprates with two-dimensional ordering of La, Ca cations and oxygen vacancies. Several phases, including the perovskites La{sub 4}Ca{sub 4}Cu{sub 8}O{sub 20}, La{sub 4}Ca{sub 4}Cu{sub 88}O{sub 18} and the Ruddlesden-Popper (RP) phase La{sub 2}Ca{sub 2}Cu{sub 3}O{sub 8}, containing three copper oxide layers (n = 3), were revealed for the first time. The results are very sensitive to experimental conditions, and a variety of reaction channels are observed at the 1:1:2 composition depending on the choice of total pressure, p{sub O}{sub 2}, temperature, and annealing conditions. The perovskite-related phases at this composition exhibited A-site cation disorder and three-dimensional ordering of oxygen vacancies. The Ruddlesden-Popper phase required the substitution of Sr on the A-sites to be metastably retained at room temperature. Due to its thermal instability, the RP phase could not be doped to a carrier concentration at which superconductivity might be observed.

Authors:
; ;  [1]
  1. Thomas J. Watson Research Center, Yorktown Heights, NY (United States)
Publication Date:
OSTI Identifier:
508641
Resource Type:
Journal Article
Journal Name:
Journal of Solid State Chemistry
Additional Journal Information:
Journal Volume: 113; Journal Issue: 1; Other Information: PBD: Nov 1994
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; LANTHANUM OXIDES; PHASE STUDIES; CALCIUM OXIDES; COPPER OXIDES; ANNEALING; CUPRATES; VACANCIES; CHEMICAL PREPARATION

Citation Formats

Guloy, A M, Scott, B A, and Figat, R A. Solid state chemistry of new perovskite and Ruddlesden-Popper phases in the La{sub 2}O{sub 3}-CaO-CuO system at high pressures. United States: N. p., 1994. Web. doi:10.1006/jssc.1994.1341.
Guloy, A M, Scott, B A, & Figat, R A. Solid state chemistry of new perovskite and Ruddlesden-Popper phases in the La{sub 2}O{sub 3}-CaO-CuO system at high pressures. United States. https://doi.org/10.1006/jssc.1994.1341
Guloy, A M, Scott, B A, and Figat, R A. 1994. "Solid state chemistry of new perovskite and Ruddlesden-Popper phases in the La{sub 2}O{sub 3}-CaO-CuO system at high pressures". United States. https://doi.org/10.1006/jssc.1994.1341.
@article{osti_508641,
title = {Solid state chemistry of new perovskite and Ruddlesden-Popper phases in the La{sub 2}O{sub 3}-CaO-CuO system at high pressures},
author = {Guloy, A M and Scott, B A and Figat, R A},
abstractNote = {The crystal chemistry of the system LaO{sub 1.5}-CaO-CuO at the 1:1:2 composition was studied at high pressures with the goal of stabilizing new perovskite cuprates with two-dimensional ordering of La, Ca cations and oxygen vacancies. Several phases, including the perovskites La{sub 4}Ca{sub 4}Cu{sub 8}O{sub 20}, La{sub 4}Ca{sub 4}Cu{sub 88}O{sub 18} and the Ruddlesden-Popper (RP) phase La{sub 2}Ca{sub 2}Cu{sub 3}O{sub 8}, containing three copper oxide layers (n = 3), were revealed for the first time. The results are very sensitive to experimental conditions, and a variety of reaction channels are observed at the 1:1:2 composition depending on the choice of total pressure, p{sub O}{sub 2}, temperature, and annealing conditions. The perovskite-related phases at this composition exhibited A-site cation disorder and three-dimensional ordering of oxygen vacancies. The Ruddlesden-Popper phase required the substitution of Sr on the A-sites to be metastably retained at room temperature. Due to its thermal instability, the RP phase could not be doped to a carrier concentration at which superconductivity might be observed.},
doi = {10.1006/jssc.1994.1341},
url = {https://www.osti.gov/biblio/508641}, journal = {Journal of Solid State Chemistry},
number = 1,
volume = 113,
place = {United States},
year = {Tue Nov 01 00:00:00 EST 1994},
month = {Tue Nov 01 00:00:00 EST 1994}
}