Topotactic redox chemistry of NaFeAs in water and air and superconducting behavior with stoichiometry change

Iliya Todorov, Duck Young Chung, Helmut Claus, Christos D. Malliakas, Alexios P. Douvalis, Thomas Bakas, Jiaqing He, Vinayak P. Dravid, Mercouri G Kanatzidis

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

We report experimental evidence that shows superconductivity in NaFeAs occurs when it is Nadeficient. The oxidation of NaFeAs progresses differently in water and in air. In water the material oxidizes slowly and slightly retaining the original anti-PbFCl structure. In air NaFeAs oxidizes topotactically quickly and extensively transforming to the ThCr2Si2 structure type. Water acts as a mild oxidizing agent on the FeAs layer by extracting electrons and Na+ cations from the structure, while oxidation in air is more extensive and leads to change in structure type from NaFeAs to NaFe 2As2. The superconducting transition temperature moves dramatically during the oxidation process. Exposed to water for an extended time period NaFeAs shows a substantial increase in Tc up to 25 K with contraction of unit cell volume. NaFe2As2, the air oxidized product, shows Tc of 12 K. We report detailed characterization of the redox chemistry and transformation of NaFeAs in water and air using single crystal and powder X-ray diffraction, magnetization studies, transmission electron microscopy,Mössbauer spectroscopy, pOH and elemental analysis.

Original languageEnglish
Pages (from-to)3916-3925
Number of pages10
JournalChemistry of Materials
Volume22
Issue number13
DOIs
Publication statusPublished - Jul 13 2010

Fingerprint

Stoichiometry
Water
Air
Oxidation
Superconductivity
Oxidants
X ray powder diffraction
Superconducting transition temperature
Cations
Magnetization
Positive ions
Oxidation-Reduction
Single crystals
Spectroscopy
Transmission electron microscopy
Electrons
Chemical analysis

ASJC Scopus subject areas

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

Cite this

Topotactic redox chemistry of NaFeAs in water and air and superconducting behavior with stoichiometry change. / Todorov, Iliya; Chung, Duck Young; Claus, Helmut; Malliakas, Christos D.; Douvalis, Alexios P.; Bakas, Thomas; He, Jiaqing; Dravid, Vinayak P.; Kanatzidis, Mercouri G.

In: Chemistry of Materials, Vol. 22, No. 13, 13.07.2010, p. 3916-3925.

Research output: Contribution to journalArticle

Todorov, I, Chung, DY, Claus, H, Malliakas, CD, Douvalis, AP, Bakas, T, He, J, Dravid, VP & Kanatzidis, MG 2010, 'Topotactic redox chemistry of NaFeAs in water and air and superconducting behavior with stoichiometry change', Chemistry of Materials, vol. 22, no. 13, pp. 3916-3925. https://doi.org/10.1021/cm100252r
Todorov, Iliya ; Chung, Duck Young ; Claus, Helmut ; Malliakas, Christos D. ; Douvalis, Alexios P. ; Bakas, Thomas ; He, Jiaqing ; Dravid, Vinayak P. ; Kanatzidis, Mercouri G. / Topotactic redox chemistry of NaFeAs in water and air and superconducting behavior with stoichiometry change. In: Chemistry of Materials. 2010 ; Vol. 22, No. 13. pp. 3916-3925.
@article{79213f4b271340a8abfacaf4d0eaeb05,
title = "Topotactic redox chemistry of NaFeAs in water and air and superconducting behavior with stoichiometry change",
abstract = "We report experimental evidence that shows superconductivity in NaFeAs occurs when it is Nadeficient. The oxidation of NaFeAs progresses differently in water and in air. In water the material oxidizes slowly and slightly retaining the original anti-PbFCl structure. In air NaFeAs oxidizes topotactically quickly and extensively transforming to the ThCr2Si2 structure type. Water acts as a mild oxidizing agent on the FeAs layer by extracting electrons and Na+ cations from the structure, while oxidation in air is more extensive and leads to change in structure type from NaFeAs to NaFe 2As2. The superconducting transition temperature moves dramatically during the oxidation process. Exposed to water for an extended time period NaFeAs shows a substantial increase in Tc up to 25 K with contraction of unit cell volume. NaFe2As2, the air oxidized product, shows Tc of 12 K. We report detailed characterization of the redox chemistry and transformation of NaFeAs in water and air using single crystal and powder X-ray diffraction, magnetization studies, transmission electron microscopy,M{\"o}ssbauer spectroscopy, pOH and elemental analysis.",
author = "Iliya Todorov and Chung, {Duck Young} and Helmut Claus and Malliakas, {Christos D.} and Douvalis, {Alexios P.} and Thomas Bakas and Jiaqing He and Dravid, {Vinayak P.} and Kanatzidis, {Mercouri G}",
year = "2010",
month = "7",
day = "13",
doi = "10.1021/cm100252r",
language = "English",
volume = "22",
pages = "3916--3925",
journal = "Chemistry of Materials",
issn = "0897-4756",
publisher = "American Chemical Society",
number = "13",

}

TY - JOUR

T1 - Topotactic redox chemistry of NaFeAs in water and air and superconducting behavior with stoichiometry change

AU - Todorov, Iliya

AU - Chung, Duck Young

AU - Claus, Helmut

AU - Malliakas, Christos D.

AU - Douvalis, Alexios P.

AU - Bakas, Thomas

AU - He, Jiaqing

AU - Dravid, Vinayak P.

AU - Kanatzidis, Mercouri G

PY - 2010/7/13

Y1 - 2010/7/13

N2 - We report experimental evidence that shows superconductivity in NaFeAs occurs when it is Nadeficient. The oxidation of NaFeAs progresses differently in water and in air. In water the material oxidizes slowly and slightly retaining the original anti-PbFCl structure. In air NaFeAs oxidizes topotactically quickly and extensively transforming to the ThCr2Si2 structure type. Water acts as a mild oxidizing agent on the FeAs layer by extracting electrons and Na+ cations from the structure, while oxidation in air is more extensive and leads to change in structure type from NaFeAs to NaFe 2As2. The superconducting transition temperature moves dramatically during the oxidation process. Exposed to water for an extended time period NaFeAs shows a substantial increase in Tc up to 25 K with contraction of unit cell volume. NaFe2As2, the air oxidized product, shows Tc of 12 K. We report detailed characterization of the redox chemistry and transformation of NaFeAs in water and air using single crystal and powder X-ray diffraction, magnetization studies, transmission electron microscopy,Mössbauer spectroscopy, pOH and elemental analysis.

AB - We report experimental evidence that shows superconductivity in NaFeAs occurs when it is Nadeficient. The oxidation of NaFeAs progresses differently in water and in air. In water the material oxidizes slowly and slightly retaining the original anti-PbFCl structure. In air NaFeAs oxidizes topotactically quickly and extensively transforming to the ThCr2Si2 structure type. Water acts as a mild oxidizing agent on the FeAs layer by extracting electrons and Na+ cations from the structure, while oxidation in air is more extensive and leads to change in structure type from NaFeAs to NaFe 2As2. The superconducting transition temperature moves dramatically during the oxidation process. Exposed to water for an extended time period NaFeAs shows a substantial increase in Tc up to 25 K with contraction of unit cell volume. NaFe2As2, the air oxidized product, shows Tc of 12 K. We report detailed characterization of the redox chemistry and transformation of NaFeAs in water and air using single crystal and powder X-ray diffraction, magnetization studies, transmission electron microscopy,Mössbauer spectroscopy, pOH and elemental analysis.

UR - http://www.scopus.com/inward/record.url?scp=78651314071&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=78651314071&partnerID=8YFLogxK

U2 - 10.1021/cm100252r

DO - 10.1021/cm100252r

M3 - Article

VL - 22

SP - 3916

EP - 3925

JO - Chemistry of Materials

JF - Chemistry of Materials

SN - 0897-4756

IS - 13

ER -