Oxygen deficiency and electrical conductivity of Nd1-xAxNiO3-y (A = alkaline earth) prepared by the low-temperature process

Shinobu Fujihara, Goki Murakami, Toshio Kimura

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The structure and electrical conductivity of oxygen-deficient Nd1-xAxNiO3-y (A = alkaline earth) have been investigated. The samples were prepared from aqueous solutions of metal acetates and EDTA by the low-temperature process. Single-phase NdNiO3-y and alkaline earth-substituted Nd0.95A0.05NiO3-y (A = Mg, Ca and Sr) were obtained by heating at 700 °C for 20 h in flowing oxygen. All the samples had large numbers of oxygen vacancies with y = 0.25-0.28, resulting in the mixed valence state of Ni2+/Ni3+, as confirmed by iodometric titration and XPS measurements. The lattice constants of the alkaline earth-substituted samples were larger than those of the non-substituted sample. These results were attributed to the difference in ionic radius. The substitution of alkaline earths for Nd decreased the decomposition temperature. All the samples showed resistivity on the order of 10-1 Ω cm at room temperature, and the temperature dependence of the electrical resistance revealed the transition from metallic to semiconducting at lower temperatures. The transition temperature was dependent on the substituted alkaline earths. This behavior is discussed in terms of the changes in lattice constants as well as in the valence of Ni resulting from the oxygen deficiency.

Original languageEnglish
Pages (from-to)70-76
Number of pages7
JournalJournal of Alloys and Compounds
Volume243
Issue number1-2
Publication statusPublished - 1996 Oct 15

Fingerprint

Earth (planet)
Oxygen
Lattice constants
Temperature
Acoustic impedance
Ethylenediaminetetraacetic acid
Oxygen vacancies
Titration
Edetic Acid
Superconducting transition temperature
Acetates
Substitution reactions
X ray photoelectron spectroscopy
Metals
Electric Conductivity
Decomposition
Heating

Keywords

  • Electrical conductivity
  • NdNiO
  • Oxygen deficiency
  • Perovskite

ASJC Scopus subject areas

  • Metals and Alloys

Cite this

Oxygen deficiency and electrical conductivity of Nd1-xAxNiO3-y (A = alkaline earth) prepared by the low-temperature process. / Fujihara, Shinobu; Murakami, Goki; Kimura, Toshio.

In: Journal of Alloys and Compounds, Vol. 243, No. 1-2, 15.10.1996, p. 70-76.

Research output: Contribution to journalArticle

@article{1ff56b280d52485fb1edb5292a79825c,
title = "Oxygen deficiency and electrical conductivity of Nd1-xAxNiO3-y (A = alkaline earth) prepared by the low-temperature process",
abstract = "The structure and electrical conductivity of oxygen-deficient Nd1-xAxNiO3-y (A = alkaline earth) have been investigated. The samples were prepared from aqueous solutions of metal acetates and EDTA by the low-temperature process. Single-phase NdNiO3-y and alkaline earth-substituted Nd0.95A0.05NiO3-y (A = Mg, Ca and Sr) were obtained by heating at 700 °C for 20 h in flowing oxygen. All the samples had large numbers of oxygen vacancies with y = 0.25-0.28, resulting in the mixed valence state of Ni2+/Ni3+, as confirmed by iodometric titration and XPS measurements. The lattice constants of the alkaline earth-substituted samples were larger than those of the non-substituted sample. These results were attributed to the difference in ionic radius. The substitution of alkaline earths for Nd decreased the decomposition temperature. All the samples showed resistivity on the order of 10-1 Ω cm at room temperature, and the temperature dependence of the electrical resistance revealed the transition from metallic to semiconducting at lower temperatures. The transition temperature was dependent on the substituted alkaline earths. This behavior is discussed in terms of the changes in lattice constants as well as in the valence of Ni resulting from the oxygen deficiency.",
keywords = "Electrical conductivity, NdNiO, Oxygen deficiency, Perovskite",
author = "Shinobu Fujihara and Goki Murakami and Toshio Kimura",
year = "1996",
month = "10",
day = "15",
language = "English",
volume = "243",
pages = "70--76",
journal = "Journal of Alloys and Compounds",
issn = "0925-8388",
publisher = "Elsevier BV",
number = "1-2",

}

TY - JOUR

T1 - Oxygen deficiency and electrical conductivity of Nd1-xAxNiO3-y (A = alkaline earth) prepared by the low-temperature process

AU - Fujihara, Shinobu

AU - Murakami, Goki

AU - Kimura, Toshio

PY - 1996/10/15

Y1 - 1996/10/15

N2 - The structure and electrical conductivity of oxygen-deficient Nd1-xAxNiO3-y (A = alkaline earth) have been investigated. The samples were prepared from aqueous solutions of metal acetates and EDTA by the low-temperature process. Single-phase NdNiO3-y and alkaline earth-substituted Nd0.95A0.05NiO3-y (A = Mg, Ca and Sr) were obtained by heating at 700 °C for 20 h in flowing oxygen. All the samples had large numbers of oxygen vacancies with y = 0.25-0.28, resulting in the mixed valence state of Ni2+/Ni3+, as confirmed by iodometric titration and XPS measurements. The lattice constants of the alkaline earth-substituted samples were larger than those of the non-substituted sample. These results were attributed to the difference in ionic radius. The substitution of alkaline earths for Nd decreased the decomposition temperature. All the samples showed resistivity on the order of 10-1 Ω cm at room temperature, and the temperature dependence of the electrical resistance revealed the transition from metallic to semiconducting at lower temperatures. The transition temperature was dependent on the substituted alkaline earths. This behavior is discussed in terms of the changes in lattice constants as well as in the valence of Ni resulting from the oxygen deficiency.

AB - The structure and electrical conductivity of oxygen-deficient Nd1-xAxNiO3-y (A = alkaline earth) have been investigated. The samples were prepared from aqueous solutions of metal acetates and EDTA by the low-temperature process. Single-phase NdNiO3-y and alkaline earth-substituted Nd0.95A0.05NiO3-y (A = Mg, Ca and Sr) were obtained by heating at 700 °C for 20 h in flowing oxygen. All the samples had large numbers of oxygen vacancies with y = 0.25-0.28, resulting in the mixed valence state of Ni2+/Ni3+, as confirmed by iodometric titration and XPS measurements. The lattice constants of the alkaline earth-substituted samples were larger than those of the non-substituted sample. These results were attributed to the difference in ionic radius. The substitution of alkaline earths for Nd decreased the decomposition temperature. All the samples showed resistivity on the order of 10-1 Ω cm at room temperature, and the temperature dependence of the electrical resistance revealed the transition from metallic to semiconducting at lower temperatures. The transition temperature was dependent on the substituted alkaline earths. This behavior is discussed in terms of the changes in lattice constants as well as in the valence of Ni resulting from the oxygen deficiency.

KW - Electrical conductivity

KW - NdNiO

KW - Oxygen deficiency

KW - Perovskite

UR - http://www.scopus.com/inward/record.url?scp=0030261854&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0030261854&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0030261854

VL - 243

SP - 70

EP - 76

JO - Journal of Alloys and Compounds

JF - Journal of Alloys and Compounds

SN - 0925-8388

IS - 1-2

ER -