Effect of the post-deposition processing ambient on the preparation of superconducting YBa2Cu3O7−<i>x</i> coevaporated thin films using a BaF2 source

Chan, Siu‐Wai; Bagley, B. G.; Greene, L. H.; Giroud, M.; Feldmann, W. L.; Jenkin, K. R.; Wilkins, Bert

doi:10.1063/1.100463

Cited by 70 publications

(11 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…E X SITU processes for the production of (RBCO; R is a rare earth of Y) epitaxial films from deposited fluoride precursors involve a high-temperature anneal, conditioned to bring about a controlled decomposition reaction of constituent fluorides in the presence of supplied water vapor [1]. Fluorides may be in the form of , Ba(F, ), or (Ba,R)(F,O), depending on the deposition method at hand, i.e.…”

Section: Introductionmentioning

confidence: 99%

A Modular Ex Situ Conversion Process for Thick MOD-Fluoride RBCO Precursors

Feenstra

List

et al. 2009

IEEE Trans. Appl. Supercond.

View full text Add to dashboard Cite

Following a review of heating induced chemical and structural changes in RBa 2 Cu 3 O 7 (RBCO) fluoride precursors (R = rare earth of Y) deposited by metalorganic deposition (MOD) and physical vapor deposition (PVD), a modular process comprising successive, functionally distinct, brief annealing steps (modules) is introduced. By decoupling events that otherwise occur simultaneously, the modular process provides a framework for addressing the complex kinetics associated with the temperature ramp of the ex situ conversion anneal. Modules for modifying the F concentration, porosity and microstructure, and RBCO nucleation are described.

show abstract

Section: Introductionmentioning

confidence: 99%

A Modular Ex Situ Conversion Process for Thick MOD-Fluoride RBCO Precursors

Feenstra

List

et al. 2009

IEEE Trans. Appl. Supercond.

View full text Add to dashboard Cite

show abstract

“…The thermodynamic data used to calculate the Gibbs free energy of the reactions can be found in the NIST-JANAF table [8]. The partial pressure of water is 4.2% usually, the partial pressure of HF varied with the change of temperature and the partial pressure of water, assumed that the partial pressure of P HF /P H2O are 1 and 1×10 -8 [9] respectively, so the ratio of P 2 HF /P H2O are 4.2×10 -2 and 4.2×10 -18 . The ∆G of reaction (2) and (3) were very close and the values were always above zero at the same partial pressure of HF when P HF /P H2O were 1 as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Phase transition during sintering process before nucleation of TFA-MOD YBa2Cu3O7-δ films

Dou

Liu

et al. 2015

2015 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices (ASEMD)

View full text Add to dashboard Cite

In order to bring new insights to the transformation mechanism of intermediate phase and its dependence on processing conditions via trifluoroacetate metal organic deposition (TFA-MOD) method, a series of quenching experiments with different annealing temperature and atmospheres were designed. It was revealed that the transformation temperature of Ba-Y-F solid solution was lower with increasing the partial pressure of water. Calculation results of the Gibbs free energy change with different partial pressure of HF and H 2 O illustrated that the intermediate process is dominated by the exit diffusion of fluorine and the higher concentration of HF will inhibit the hydrolysis of barium fluoride.

show abstract

“…This is clear from our results presented above and the results of several other groups. [1][2][3][4][5][6][7][27][28][29] McIntyre et al have reported on the J c dependence of film thickness for similar post annealed films. 27 They showed that there is a correlation between the density of 1-2-4 stacking faults and J c in that the 1-2-4 stacking faults act as planar core type flux pinning centers thereby increasing J c .…”

Section: Discussionmentioning

confidence: 99%

“…The BaF 2 coevaporation technique has proven superior in combination with optimized ex situ post annealing at low oxygen partial pressures. [1][2][3][4][5][6][7] In general, films processed under these conditions have a good surface morphology with no large surface outgrowths, high transition temperatures (T c ), high values of the critical current density (J c ) and good microwave properties. [3][4][5][6][7] These good properties can be obtained only if the YBCO thin films are grown on special substrates.…”

Section: Introductionmentioning

confidence: 99%

Improved current transport properties of post annealed Y1Ba2Cu3O7−x thin films using Ag doping

Clausen

Skov

Jacobsen

et al. 1996

Journal of Applied Physics

View full text Add to dashboard Cite

The influence of Ag doping on the transport properties of Y 1 Ba 2 Cu 3 O 7Ϫx thin films prepared by Y, BaF 2 , and Cu co-evaporation and optimized ex situ post annealing has been investigated. Both undoped and Ag doped films have values of T c above 90 K, but J c ͑77 K͒ is highly dependent on the nominal thickness ͑t nom ͒ of the as-deposited film. For undoped films with t nom р300 nm J c ͑77 K͒ ͑ӷ10 6 A/cm 2 ͒ decreases monotonically with increasing film thickness. Above 300 nm J c ͑77 K͒ decreases rapidly to values below 5ϫ10 5 A/cm 2 . Ag doped films with t nom у200 nm have higher J c ͑77 K͒ values than those of undoped films. Ag doped films have a maximum in J c ͑77 K͒ around 250 nm. As for the undoped films, there is a large decrease in J c ͑77 K͒ for Ag doped films with t nom у300 nm. It was found that the higher values of J c ͑77 K͒ for the Ag doped films were due to a better epitaxial growth of the YBCO compound. The low values of J c ͑77 K͒ for both undoped and Ag doped single layer films with t nom у300 nm were found to be due to the absence of 1-2-4 inclusions in these films. Based on these findings high J c ͑77 K͒ films with t nom Ͼ300 nm were grown by successive deposition and annealing of films with t nom Ͻ300 nm on top of each other. A 2ϫ150 nm undoped film was found to have a J c ͑77 K͒ value of 4, 1ϫ10 6 A/cm 2 . This is almost a doubling of the J c ͑77 K͒ value as compared to the value for the 300 nm single layer undoped film ͑2,2ϫ10 6 A/cm 2 ͒. Ag doped double layer films of 2ϫ150 nm and 2ϫ215 nm had comparable J c ͑77 K͒ values ͑5,8ϫ10 6 and 5,6ϫ10 6 A/cm 2 , respectively͒. In comparison with the undoped 2ϫ150 nm film J c ͑77 K͒ is thus further increased ͑by about 50%͒ when doping with Ag.

show abstract

Effect of the post-deposition processing ambient on the preparation of superconducting YBa2Cu3O7−x coevaporated thin films using a BaF2 source

Cited by 70 publications

References 13 publications

A Modular Ex Situ Conversion Process for Thick MOD-Fluoride RBCO Precursors

A Modular Ex Situ Conversion Process for Thick MOD-Fluoride RBCO Precursors

Phase transition during sintering process before nucleation of TFA-MOD YBa2Cu3O7-δ films

Improved current transport properties of post annealed Y1Ba2Cu3O7−x thin films using Ag doping

Contact Info

Product

Resources

About