Superconducting La1.5-xBa1.5 + x-yCayCu3Oz solid solutions II. Oxygen content and crystal structure

J. M.S. Skakle* (Corresponding Author), A. R. West

*Corresponding author for this work

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

The La1.5-xBa1.5 + x-yCayCu3Oz solid solutions have properties that vary from semiconducting (x=y=0) to super conducting with Tc=78 K (x=y=0.5). The latter are of special interest since they are tetragonal. Rietveld refinement of powder X-ray diffraction data confirms that Ca substitutes onto the La sites, with concomitant displacement of La onto the Ba sites and that the solid solutions are based on the 336 formula, La1.55Ba1.5Cu3Oz rather than on 123, LaBa2Cu3Oz. The oxygen con tents have been determined by H2 reduction. With increasing x, the oxygen content is unchanged as Ba substitutes for La and therefore charge compensation is achieved by hole creation. With substitution of Ba by Ca, i.e. increasing y, additional oxygen is incorporated into the structure and, again, holes are created to preserve charge balance. A good correlation between TC and average Cu valence is found.

Original languageEnglish
Pages (from-to)336-342
Number of pages7
JournalPhysica C: Superconductivity and its Applications
Volume227
Issue number3-4
DOIs
Publication statusPublished - 1 Jul 1994

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Solid solutions
solid solutions
Crystal structure
substitutes
Oxygen
crystal structure
oxygen
Rietveld refinement
X ray powder diffraction
Substitution reactions
valence
conduction
diffraction
x rays
Compensation and Redress

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering

Cite this

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title = "Superconducting La1.5-xBa1.5 + x-yCayCu3Oz solid solutions II. Oxygen content and crystal structure",
abstract = "The La1.5-xBa1.5 + x-yCayCu3Oz solid solutions have properties that vary from semiconducting (x=y=0) to super conducting with Tc=78 K (x=y=0.5). The latter are of special interest since they are tetragonal. Rietveld refinement of powder X-ray diffraction data confirms that Ca substitutes onto the La sites, with concomitant displacement of La onto the Ba sites and that the solid solutions are based on the 336 formula, La1.55Ba1.5Cu3Oz rather than on 123, LaBa2Cu3Oz. The oxygen con tents have been determined by H2 reduction. With increasing x, the oxygen content is unchanged as Ba substitutes for La and therefore charge compensation is achieved by hole creation. With substitution of Ba by Ca, i.e. increasing y, additional oxygen is incorporated into the structure and, again, holes are created to preserve charge balance. A good correlation between TC and average Cu valence is found.",
author = "Skakle, {J. M.S.} and West, {A. R.}",
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N2 - The La1.5-xBa1.5 + x-yCayCu3Oz solid solutions have properties that vary from semiconducting (x=y=0) to super conducting with Tc=78 K (x=y=0.5). The latter are of special interest since they are tetragonal. Rietveld refinement of powder X-ray diffraction data confirms that Ca substitutes onto the La sites, with concomitant displacement of La onto the Ba sites and that the solid solutions are based on the 336 formula, La1.55Ba1.5Cu3Oz rather than on 123, LaBa2Cu3Oz. The oxygen con tents have been determined by H2 reduction. With increasing x, the oxygen content is unchanged as Ba substitutes for La and therefore charge compensation is achieved by hole creation. With substitution of Ba by Ca, i.e. increasing y, additional oxygen is incorporated into the structure and, again, holes are created to preserve charge balance. A good correlation between TC and average Cu valence is found.

AB - The La1.5-xBa1.5 + x-yCayCu3Oz solid solutions have properties that vary from semiconducting (x=y=0) to super conducting with Tc=78 K (x=y=0.5). The latter are of special interest since they are tetragonal. Rietveld refinement of powder X-ray diffraction data confirms that Ca substitutes onto the La sites, with concomitant displacement of La onto the Ba sites and that the solid solutions are based on the 336 formula, La1.55Ba1.5Cu3Oz rather than on 123, LaBa2Cu3Oz. The oxygen con tents have been determined by H2 reduction. With increasing x, the oxygen content is unchanged as Ba substitutes for La and therefore charge compensation is achieved by hole creation. With substitution of Ba by Ca, i.e. increasing y, additional oxygen is incorporated into the structure and, again, holes are created to preserve charge balance. A good correlation between TC and average Cu valence is found.

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