A novel sol-gel route to superconducting oxyfluoride Sr2Cu(O,F)y thin films

S. Fujihara; Y. Masuda; J. S. Jin; T. Kimura; K. Tanabe

doi:10.1016/S0921-4534(97)00176-7

A novel sol-gel route to superconducting oxyfluoride Sr₂Cu(O,F)_y thin films

S. Fujihara, Y. Masuda, J. S. Jin, T. Kimura, K. Tanabe

Department of Applied Chemistry

Research output: Contribution to journal › Article › peer-review

1 Citation (Scopus)

Abstract

Oxyfluoride Sr₂Cu(O,F)_y thin films were prepared by a sol-gel method using Sr(O-iC₃H₇)₂ and CuF₂ as starting materials and trifluoroacetic acid as an additional fluorine source. The sols were coated on SrTiO₃ (STO) or LaAlO₃ (LAO) single crystal substrates and then heated at 800°C under a condition controlled by the concentration of O₂ gas. For the films on STO, Sr₂CuO₃ was formed first and changed to the K₂NiF₄-type Sr₂Cu(O,F)_y phase by post-fluorination using a methanol solution of NH₄F. In the case of using LAO substrates, the Sr₂Cu(O,F)_y phase was directly formed by one time heating at 800°C. A direct formation of the Sr₂Cu(O,F)_y phase has never been reported before. The presence of fluorine in the films was confirmed both by chemical analysis and XPS spectroscopy. The discrepancy in the crystallization behavior of the films on STO and on LAO substrates is explained by the formation of SrF₂ impurities owing to the reaction between fluorine in the film and strontium in the STO substrate. The Sr₂Cu(O,F)_y thin films on STO exhibited the superconducting transition at 45 K in a SQUID measurement.

Original language	English
Pages (from-to)	115-120
Number of pages	6
Journal	Physica C: Superconductivity and its applications
Volume	280
Issue number	3
DOIs	https://doi.org/10.1016/S0921-4534(97)00176-7
Publication status	Published - 1997 Jul 1

Keywords

Oxyfluoride superconductor
Sol-gel
SrCu(O,F)
SrCuOF
Thin films

ASJC Scopus subject areas

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

Access to Document

10.1016/S0921-4534(97)00176-7

Cite this

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title = "A novel sol-gel route to superconducting oxyfluoride Sr2Cu(O,F)y thin films",

abstract = "Oxyfluoride Sr2Cu(O,F)y thin films were prepared by a sol-gel method using Sr(O-iC3H7)2 and CuF2 as starting materials and trifluoroacetic acid as an additional fluorine source. The sols were coated on SrTiO3 (STO) or LaAlO3 (LAO) single crystal substrates and then heated at 800°C under a condition controlled by the concentration of O2 gas. For the films on STO, Sr2CuO3 was formed first and changed to the K2NiF4-type Sr2Cu(O,F)y phase by post-fluorination using a methanol solution of NH4F. In the case of using LAO substrates, the Sr2Cu(O,F)y phase was directly formed by one time heating at 800°C. A direct formation of the Sr2Cu(O,F)y phase has never been reported before. The presence of fluorine in the films was confirmed both by chemical analysis and XPS spectroscopy. The discrepancy in the crystallization behavior of the films on STO and on LAO substrates is explained by the formation of SrF2 impurities owing to the reaction between fluorine in the film and strontium in the STO substrate. The Sr2Cu(O,F)y thin films on STO exhibited the superconducting transition at 45 K in a SQUID measurement.",

keywords = "Oxyfluoride superconductor, Sol-gel, SrCu(O,F), SrCuOF, Thin films",

author = "S. Fujihara and Y. Masuda and Jin, {J. S.} and T. Kimura and K. Tanabe",

year = "1997",

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T1 - A novel sol-gel route to superconducting oxyfluoride Sr2Cu(O,F)y thin films

AU - Fujihara, S.

AU - Masuda, Y.

AU - Jin, J. S.

AU - Kimura, T.

AU - Tanabe, K.

PY - 1997/7/1

Y1 - 1997/7/1

N2 - Oxyfluoride Sr2Cu(O,F)y thin films were prepared by a sol-gel method using Sr(O-iC3H7)2 and CuF2 as starting materials and trifluoroacetic acid as an additional fluorine source. The sols were coated on SrTiO3 (STO) or LaAlO3 (LAO) single crystal substrates and then heated at 800°C under a condition controlled by the concentration of O2 gas. For the films on STO, Sr2CuO3 was formed first and changed to the K2NiF4-type Sr2Cu(O,F)y phase by post-fluorination using a methanol solution of NH4F. In the case of using LAO substrates, the Sr2Cu(O,F)y phase was directly formed by one time heating at 800°C. A direct formation of the Sr2Cu(O,F)y phase has never been reported before. The presence of fluorine in the films was confirmed both by chemical analysis and XPS spectroscopy. The discrepancy in the crystallization behavior of the films on STO and on LAO substrates is explained by the formation of SrF2 impurities owing to the reaction between fluorine in the film and strontium in the STO substrate. The Sr2Cu(O,F)y thin films on STO exhibited the superconducting transition at 45 K in a SQUID measurement.

AB - Oxyfluoride Sr2Cu(O,F)y thin films were prepared by a sol-gel method using Sr(O-iC3H7)2 and CuF2 as starting materials and trifluoroacetic acid as an additional fluorine source. The sols were coated on SrTiO3 (STO) or LaAlO3 (LAO) single crystal substrates and then heated at 800°C under a condition controlled by the concentration of O2 gas. For the films on STO, Sr2CuO3 was formed first and changed to the K2NiF4-type Sr2Cu(O,F)y phase by post-fluorination using a methanol solution of NH4F. In the case of using LAO substrates, the Sr2Cu(O,F)y phase was directly formed by one time heating at 800°C. A direct formation of the Sr2Cu(O,F)y phase has never been reported before. The presence of fluorine in the films was confirmed both by chemical analysis and XPS spectroscopy. The discrepancy in the crystallization behavior of the films on STO and on LAO substrates is explained by the formation of SrF2 impurities owing to the reaction between fluorine in the film and strontium in the STO substrate. The Sr2Cu(O,F)y thin films on STO exhibited the superconducting transition at 45 K in a SQUID measurement.

KW - Oxyfluoride superconductor

KW - Sol-gel

KW - SrCu(O,F)

KW - SrCuOF

KW - Thin films

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