A low-fluorine solution with a 2:1 F/Ba mole ratio for the fabrication of YBCO films

Paper

Wei Wu, Feng Feng, Zhao Yue, Xiao Tang, Yunran Xue, Kai Shi, Rongxia Huang, Timing Qu, Xiaohao Wang, Zhenghe Han, Jean-Claude Grivel

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

In previously reported low-fluorine MOD-YBCO studies, the lowest F/Ba mole ratio of the precursor solution was 4.5. Further lowering the F/Ba ratio would bring benefits for the environment, thick film deposition, and an understanding of the heat treatment process. On the other hand, the F/Ba ratio must be at least 2 for full conversion of the Ba-precursor to BaF2 to avoid the formation of BaCO3, which is detrimental to the superconducting performance of YBCO films. In this study, a solution with a 2:1 F/Ba mole ratio was developed, and the fluorine content of this solution was approximately only 10.3% of that used in the conventional TFA-MOD method. Attenuated total reflectance-Fourier transform-infrared spectra (ATR-FT-IR) revealed that BaCO3 was remarkably suppressed in the as-pyrolyzed film—and eliminated at 700 °C. Thus, YBCO films with a critical current density (Jc) of over 5 MA cm−2 (77 K, 0 T, 200 nm thickness) could be obtained on lanthanum aluminate single-crystal substrates. In situ FT-IR spectra showed that no obvious fluorinated gaseous by-products were detected in the pyrolysis step, which indicated that all F atoms might remain in the film as fluorides. X-ray diffraction θ/2θ scans showed the presence of BaF2—but not of Y F3 or CuF2—in films quenched at 400–800 °C. The formation priority of BaF2 over Y F3 and CuF2 was interpreted by examining the chemical equilibrium of the potential reactions. Our study could enlarge the synthesis window of precursor solutions for MOD-YBCO fabrication, and serve as a foundation for continuously and systematically studying the influence of fluorine content in the precursor solutions.
Original languageEnglish
Article number055006
JournalSuperconductor Science & Technology
Volume27
Issue number5
Number of pages10
ISSN0953-2048
DOIs
Publication statusPublished - 2014

Keywords

  • YBCO film
  • Low-fluorine
  • F=Ba ratio
  • Phase evolution
  • Chemical equilibrium

Cite this

Wu, Wei ; Feng, Feng ; Yue, Zhao ; Tang, Xiao ; Xue, Yunran ; Shi, Kai ; Huang, Rongxia ; Qu, Timing ; Wang, Xiaohao ; Han, Zhenghe ; Grivel, Jean-Claude. / A low-fluorine solution with a 2:1 F/Ba mole ratio for the fabrication of YBCO films : Paper. In: Superconductor Science & Technology. 2014 ; Vol. 27, No. 5.
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abstract = "In previously reported low-fluorine MOD-YBCO studies, the lowest F/Ba mole ratio of the precursor solution was 4.5. Further lowering the F/Ba ratio would bring benefits for the environment, thick film deposition, and an understanding of the heat treatment process. On the other hand, the F/Ba ratio must be at least 2 for full conversion of the Ba-precursor to BaF2 to avoid the formation of BaCO3, which is detrimental to the superconducting performance of YBCO films. In this study, a solution with a 2:1 F/Ba mole ratio was developed, and the fluorine content of this solution was approximately only 10.3{\%} of that used in the conventional TFA-MOD method. Attenuated total reflectance-Fourier transform-infrared spectra (ATR-FT-IR) revealed that BaCO3 was remarkably suppressed in the as-pyrolyzed film—and eliminated at 700 °C. Thus, YBCO films with a critical current density (Jc) of over 5 MA cm−2 (77 K, 0 T, 200 nm thickness) could be obtained on lanthanum aluminate single-crystal substrates. In situ FT-IR spectra showed that no obvious fluorinated gaseous by-products were detected in the pyrolysis step, which indicated that all F atoms might remain in the film as fluorides. X-ray diffraction θ/2θ scans showed the presence of BaF2—but not of Y F3 or CuF2—in films quenched at 400–800 °C. The formation priority of BaF2 over Y F3 and CuF2 was interpreted by examining the chemical equilibrium of the potential reactions. Our study could enlarge the synthesis window of precursor solutions for MOD-YBCO fabrication, and serve as a foundation for continuously and systematically studying the influence of fluorine content in the precursor solutions.",
keywords = "YBCO film, Low-fluorine, F=Ba ratio, Phase evolution, Chemical equilibrium",
author = "Wei Wu and Feng Feng and Zhao Yue and Xiao Tang and Yunran Xue and Kai Shi and Rongxia Huang and Timing Qu and Xiaohao Wang and Zhenghe Han and Jean-Claude Grivel",
year = "2014",
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language = "English",
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A low-fluorine solution with a 2:1 F/Ba mole ratio for the fabrication of YBCO films : Paper. / Wu, Wei; Feng, Feng; Yue, Zhao; Tang, Xiao; Xue, Yunran; Shi, Kai; Huang, Rongxia; Qu, Timing; Wang, Xiaohao; Han, Zhenghe; Grivel, Jean-Claude.

In: Superconductor Science & Technology, Vol. 27, No. 5, 055006, 2014.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - A low-fluorine solution with a 2:1 F/Ba mole ratio for the fabrication of YBCO films

T2 - Paper

AU - Wu, Wei

AU - Feng, Feng

AU - Yue, Zhao

AU - Tang, Xiao

AU - Xue, Yunran

AU - Shi, Kai

AU - Huang, Rongxia

AU - Qu, Timing

AU - Wang, Xiaohao

AU - Han, Zhenghe

AU - Grivel, Jean-Claude

PY - 2014

Y1 - 2014

N2 - In previously reported low-fluorine MOD-YBCO studies, the lowest F/Ba mole ratio of the precursor solution was 4.5. Further lowering the F/Ba ratio would bring benefits for the environment, thick film deposition, and an understanding of the heat treatment process. On the other hand, the F/Ba ratio must be at least 2 for full conversion of the Ba-precursor to BaF2 to avoid the formation of BaCO3, which is detrimental to the superconducting performance of YBCO films. In this study, a solution with a 2:1 F/Ba mole ratio was developed, and the fluorine content of this solution was approximately only 10.3% of that used in the conventional TFA-MOD method. Attenuated total reflectance-Fourier transform-infrared spectra (ATR-FT-IR) revealed that BaCO3 was remarkably suppressed in the as-pyrolyzed film—and eliminated at 700 °C. Thus, YBCO films with a critical current density (Jc) of over 5 MA cm−2 (77 K, 0 T, 200 nm thickness) could be obtained on lanthanum aluminate single-crystal substrates. In situ FT-IR spectra showed that no obvious fluorinated gaseous by-products were detected in the pyrolysis step, which indicated that all F atoms might remain in the film as fluorides. X-ray diffraction θ/2θ scans showed the presence of BaF2—but not of Y F3 or CuF2—in films quenched at 400–800 °C. The formation priority of BaF2 over Y F3 and CuF2 was interpreted by examining the chemical equilibrium of the potential reactions. Our study could enlarge the synthesis window of precursor solutions for MOD-YBCO fabrication, and serve as a foundation for continuously and systematically studying the influence of fluorine content in the precursor solutions.

AB - In previously reported low-fluorine MOD-YBCO studies, the lowest F/Ba mole ratio of the precursor solution was 4.5. Further lowering the F/Ba ratio would bring benefits for the environment, thick film deposition, and an understanding of the heat treatment process. On the other hand, the F/Ba ratio must be at least 2 for full conversion of the Ba-precursor to BaF2 to avoid the formation of BaCO3, which is detrimental to the superconducting performance of YBCO films. In this study, a solution with a 2:1 F/Ba mole ratio was developed, and the fluorine content of this solution was approximately only 10.3% of that used in the conventional TFA-MOD method. Attenuated total reflectance-Fourier transform-infrared spectra (ATR-FT-IR) revealed that BaCO3 was remarkably suppressed in the as-pyrolyzed film—and eliminated at 700 °C. Thus, YBCO films with a critical current density (Jc) of over 5 MA cm−2 (77 K, 0 T, 200 nm thickness) could be obtained on lanthanum aluminate single-crystal substrates. In situ FT-IR spectra showed that no obvious fluorinated gaseous by-products were detected in the pyrolysis step, which indicated that all F atoms might remain in the film as fluorides. X-ray diffraction θ/2θ scans showed the presence of BaF2—but not of Y F3 or CuF2—in films quenched at 400–800 °C. The formation priority of BaF2 over Y F3 and CuF2 was interpreted by examining the chemical equilibrium of the potential reactions. Our study could enlarge the synthesis window of precursor solutions for MOD-YBCO fabrication, and serve as a foundation for continuously and systematically studying the influence of fluorine content in the precursor solutions.

KW - YBCO film

KW - Low-fluorine

KW - F=Ba ratio

KW - Phase evolution

KW - Chemical equilibrium

U2 - 10.1088/0953-2048/27/5/055006

DO - 10.1088/0953-2048/27/5/055006

M3 - Journal article

VL - 27

JO - Superconductor Science & Technology

JF - Superconductor Science & Technology

SN - 0953-2048

IS - 5

M1 - 055006

ER -