Pyrolysis study of solution-derived superconducting YBa₂Cu₃O₇films: disentangling the physico-chemical transformations

Abstract

<p>Pyrolysis transformations, wrinkling and cracking, of thick solution-derived epitaxial superconducting YBa₂Cu₃O₇ films are disclosed through <italic>in situ</italic> analytical studies.</p>

Optimal Vortex Pinning in YBa2Cu3O7-x Superconducting Films Up to Very High Magnetic Fields

“…On the other hand, as depicted in gure 8(b), thick lms offer at 4.2 K higher total critical current I c values in comparison with the pristine thin lm up to 35 T, despite of their lower J c values. This reinforces the need to further understand and optimize the growth of thick lms (using inkjet printing in this case 73 ). Our study on CSD lms suggests that the selection of thick nanocomposite lms is especially bene cial for the design of CCs operating at the range of 5-10 T offering 6 and 2.5 times larger I c values than the thin and thick pristine lms respectively.…”

High Performance of Superconducting YBa2Cu3O7 Thick Films Prepared by Single-Deposition Inkjet Printing

“…From EGA−FTIR (Figures 5b and S10) and EGA−MS analyses, it was verified that the volatiles including TFAH and most of the propionate moieties were decomposed below ∼300 °C, similar to solution 4. 40 The last peak in the dTG appearing at T ∼ 309 °C (Figure 5b) and differential scanning calorimetry (DSC) (Figure S10) is only observed in the 4 + V film. It corresponds to CO 2 , and it is linked to the decomposition of acrylate derivatives.…”

“…In this high-temperature range of region III (T > 270 °C), as we mentioned above, a small fraction of the metalorganic skeleton (mainly acrylate derivatives) remains, while the film becomes stiffer when the transformation to a nanoporous solid occurs. 40 Therefore, it is important to preserve part of the acrylate skeleton at higher temperatures to soften the elastic solid associated to the inorganic amorphous or nanocrystalline nanoparticles, thus smoothing the shrinkage process and ensuring the film integrity. 58 We may wonder why displacing the shrinkage at higher temperatures would improve the resilience of the films against crack formation.…”

“…32,50 An additional advantage of using the varnish additive V is that TGA shows that it completes its decomposition at higher temperatures (see Figure 5) than the metalorganic salts preserving the molecular skeleton of our films. 40 Additionally, we used an additive to promote the epitaxial nucleation step (Ag TFA), while nanocomposite superconducting films were prepared by stabilizing BaZrO 3 nanoparticles in the precursor solution to enhance the in-field properties. 17,32,76 Typically, the contents were 5% mol Ag(TFA) in the first case and 12% mol BaZrO 3 in the second case.…”

“…First, the films are pyrolyzed at low temperatures (T < 500 °C) using a process which we have optimized for thick films, based on the knowledge generated in a recent thorough analysis of the physico-chemical transformations of the low-fluorine YBCO CSD films during heating in this temperature range. 40 After pyrolysis, a second high-temperature (T < 820 °C) nucleation and growth process of epitaxial YBCO thick films has been carried out. 32 The pyrolysis of the films is performed following a heating process under a humid O 2 atmosphere including three different steps characterized by the heating ramp and the temperature regions.…”