Composition-Controlled Metal–Nonmetal Transition in La2–xSrxNiO4–δ

C. J. Liu, M. D. Mays, D. O. Cowan, M. G. Sánchez

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Materials with the general composition La2–xSrxNiO4–δ retain the perovskite-related structure of space group I4/mmm up to x = 1.50. They undergo a composition-dependent metal-nonmetal transition in electrical conductivity. The composition parameters x and δ determine the conductivity type. For * < 1 the materials are nonmetals. For x > 1.1 metallic conductivity is observed that persists to a limit of at least x = 1.50 if the oxygen deficiency δ is low. For compositions near the transition the conductivity type is also dependent on δ. Metallic samples become nonmetals upon heating in flowing Ar at 1000 °C, which revert to metals upon oxidation in O2 also at 1000 °C. All nonmetal-to-metal transitions are accompanied by a change in color from black to reddish brown. The Ni average valence υ was determined from the metals composition and iodometric titration data. The δ value was calculated from υ by using the equation δ = 0.5x + (1 – 0.5υ), which was derived by using a formal valence convention. Both υ and δ increase monotonically with x in the range 0 ≤ x ≤ 1.5. A phase diagram is proposed for the metal-nonmetal transition in which the boundary is given by δ = 0.5x – 0.51, which corresponds to v ≈ 3.02. No stoichiometric 214 nickelate (δ = 0) could be prepared in the metallic region, and no superconductive transition was observed in any material down to ~3 K.

Original languageEnglish
Pages (from-to)495-500
Number of pages6
JournalChemistry of Materials
Volume3
Issue number3
DOIs
Publication statusPublished - 1991 May 1

Fingerprint

Nonmetals
Metals
Chemical analysis
Titration
Perovskite
Phase diagrams
Transition metals
Oxygen
Color
Heating
Oxidation

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

Cite this

Liu, C. J. ; Mays, M. D. ; Cowan, D. O. ; Sánchez, M. G. / Composition-Controlled Metal–Nonmetal Transition in La2–xSrxNiO4–δ. In: Chemistry of Materials. 1991 ; Vol. 3, No. 3. pp. 495-500.
@article{0b718247743a43d0b071cddc46437bea,
title = "Composition-Controlled Metal–Nonmetal Transition in La2–xSrxNiO4–δ",
abstract = "Materials with the general composition La2–xSrxNiO4–δ retain the perovskite-related structure of space group I4/mmm up to x = 1.50. They undergo a composition-dependent metal-nonmetal transition in electrical conductivity. The composition parameters x and δ determine the conductivity type. For * < 1 the materials are nonmetals. For x > 1.1 metallic conductivity is observed that persists to a limit of at least x = 1.50 if the oxygen deficiency δ is low. For compositions near the transition the conductivity type is also dependent on δ. Metallic samples become nonmetals upon heating in flowing Ar at 1000 °C, which revert to metals upon oxidation in O2 also at 1000 °C. All nonmetal-to-metal transitions are accompanied by a change in color from black to reddish brown. The Ni average valence υ was determined from the metals composition and iodometric titration data. The δ value was calculated from υ by using the equation δ = 0.5x + (1 – 0.5υ), which was derived by using a formal valence convention. Both υ and δ increase monotonically with x in the range 0 ≤ x ≤ 1.5. A phase diagram is proposed for the metal-nonmetal transition in which the boundary is given by δ = 0.5x – 0.51, which corresponds to v ≈ 3.02. No stoichiometric 214 nickelate (δ = 0) could be prepared in the metallic region, and no superconductive transition was observed in any material down to ~3 K.",
author = "Liu, {C. J.} and Mays, {M. D.} and Cowan, {D. O.} and S{\'a}nchez, {M. G.}",
year = "1991",
month = "5",
day = "1",
doi = "10.1021/cm00015a026",
language = "English",
volume = "3",
pages = "495--500",
journal = "Chemistry of Materials",
issn = "0897-4756",
publisher = "American Chemical Society",
number = "3",

}

Composition-Controlled Metal–Nonmetal Transition in La2–xSrxNiO4–δ. / Liu, C. J.; Mays, M. D.; Cowan, D. O.; Sánchez, M. G.

In: Chemistry of Materials, Vol. 3, No. 3, 01.05.1991, p. 495-500.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Composition-Controlled Metal–Nonmetal Transition in La2–xSrxNiO4–δ

AU - Liu, C. J.

AU - Mays, M. D.

AU - Cowan, D. O.

AU - Sánchez, M. G.

PY - 1991/5/1

Y1 - 1991/5/1

N2 - Materials with the general composition La2–xSrxNiO4–δ retain the perovskite-related structure of space group I4/mmm up to x = 1.50. They undergo a composition-dependent metal-nonmetal transition in electrical conductivity. The composition parameters x and δ determine the conductivity type. For * < 1 the materials are nonmetals. For x > 1.1 metallic conductivity is observed that persists to a limit of at least x = 1.50 if the oxygen deficiency δ is low. For compositions near the transition the conductivity type is also dependent on δ. Metallic samples become nonmetals upon heating in flowing Ar at 1000 °C, which revert to metals upon oxidation in O2 also at 1000 °C. All nonmetal-to-metal transitions are accompanied by a change in color from black to reddish brown. The Ni average valence υ was determined from the metals composition and iodometric titration data. The δ value was calculated from υ by using the equation δ = 0.5x + (1 – 0.5υ), which was derived by using a formal valence convention. Both υ and δ increase monotonically with x in the range 0 ≤ x ≤ 1.5. A phase diagram is proposed for the metal-nonmetal transition in which the boundary is given by δ = 0.5x – 0.51, which corresponds to v ≈ 3.02. No stoichiometric 214 nickelate (δ = 0) could be prepared in the metallic region, and no superconductive transition was observed in any material down to ~3 K.

AB - Materials with the general composition La2–xSrxNiO4–δ retain the perovskite-related structure of space group I4/mmm up to x = 1.50. They undergo a composition-dependent metal-nonmetal transition in electrical conductivity. The composition parameters x and δ determine the conductivity type. For * < 1 the materials are nonmetals. For x > 1.1 metallic conductivity is observed that persists to a limit of at least x = 1.50 if the oxygen deficiency δ is low. For compositions near the transition the conductivity type is also dependent on δ. Metallic samples become nonmetals upon heating in flowing Ar at 1000 °C, which revert to metals upon oxidation in O2 also at 1000 °C. All nonmetal-to-metal transitions are accompanied by a change in color from black to reddish brown. The Ni average valence υ was determined from the metals composition and iodometric titration data. The δ value was calculated from υ by using the equation δ = 0.5x + (1 – 0.5υ), which was derived by using a formal valence convention. Both υ and δ increase monotonically with x in the range 0 ≤ x ≤ 1.5. A phase diagram is proposed for the metal-nonmetal transition in which the boundary is given by δ = 0.5x – 0.51, which corresponds to v ≈ 3.02. No stoichiometric 214 nickelate (δ = 0) could be prepared in the metallic region, and no superconductive transition was observed in any material down to ~3 K.

UR - http://www.scopus.com/inward/record.url?scp=0039780296&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0039780296&partnerID=8YFLogxK

U2 - 10.1021/cm00015a026

DO - 10.1021/cm00015a026

M3 - Article

AN - SCOPUS:0039780296

VL - 3

SP - 495

EP - 500

JO - Chemistry of Materials

JF - Chemistry of Materials

SN - 0897-4756

IS - 3

ER -