Chemical Solution Deposition of YBCO Films with Gd Excess

Abstract

Chemical solution deposition of Gd-doped YBCO, Y1GdyBa2Cu3O7−δ, (YBCO-Gd), film was carried out following the metal‑organic decomposition approach and in situ route. Two dopant concentrations, 5 and 10 mol %, were evaluated. The morphology and crystalline structure of the superconductor films were deeply investigated. In general, a homogeneous and well c-axis oriented film was observed by using scanning and transmission electron microscopy (SEM and TEM) and X-ray diffraction. However, compared to pure YBCO, YBCO-Gd samples showed an increased stacking faults concentration, as recognized by TEM. X-ray photoelectron spectroscopy allowed studying the Gd distribution in the films and gathered information about the Gd electronic environment. Superconducting properties were evaluated at different temperatures, magnetic field directions, and intensities. Higher zero‑field critical current densities were measured with respect to undoped samples in the temperature range from 10 to 77 K with both Gd concentrations (i.e., 28, 27, and 13 MA·cm−2, respectively, for YBCO-Gd 5%, YBCO-Gd 10%, and undoped YBCO at 10 K in self field condition). At low temperatures, this improvement was maintained up to 12 T, confirming the efficacy of Gd addition for the enhancement of transport properties of YBCO film.

Nanodiamond Influence on the Nucleation and Growth of YBCO Superconducting Film Deposited by Metal–Organic Decomposition

“…The superconducting properties of fully converted YBCO+ND film confirmed the good results previously emerged. A sharp superconducting transition was observed, with a T c value as high as 90.7 K, in line with the mean value of 90.4 ± 0.2 K measured with other YBCO+ND samples and similar to the best results achieved by YBCO films grown in the same conditions ( T c = 90.2 ± 0.4 K) …”

“…A sharp superconducting transition was observed, with a T c value as high as 90.7 K, in line with the mean value a of 90.4 ± 0.2 K measured with other YBCO+ND samples and similar to the best results achieved by YBCO films grown in the same conditions a (T c = 90.2 ± 0.4 K). 6 Again, the film deposited with the solution containing ND showed an improvement of transport properties in self-field conditions that, as already hypothesized, could be originated from the excellent grain coalescence and film density, which promotes the current percolation path. 3 Nanodiamond Effect on YBCO Nucleation and Growth.…”

“…The former approach is carried out by adding the desired precursor or an excess of one element, such as Y or Gd, to the precursor solution. Metal ions exceeding the 123 RE BCO stoichiometry will form other phases. − The latter approach includes the preparation of preformed NPs, which are dispersed in the precursor solution. The main advantage of using preformed NPs is the possibility of easily customizing the size and concentration of the precursor solution.…”

Critical current density improvement in CSD-grown high-entropy REBa2Cu3O7−δ films

“…4d, continuous vertical line) at the SF (marked by arrows), depending on the orientation of the orthorhombic REBCO structure. 43,46 The [100] or [010] orientation can switch along the [001] direction 43,[46][47][48][49] which can be observed in Fig. 4c and d.…”

Development of a Fluorine-Free Polymer-Assisted-Deposition Route for YBa2Cu3O7−x Superconducting Films

“…However, one of the major drawbacks of this method is the liberation of toxic HF during the YBCO pyrolysis/crystallization steps [5]. Continuous efforts are being carried out in the development of low-fluorine (see for example [6,7]) and fluorine-free chemical solution deposition processes [8][9][10][11][12]. These approaches consist of dissolving carboxylates, such as acetates, propionates, etc., or β-diketonates, as metal precursors in a common solvent, usually organic acids, and combining the solutions to yield the desired stoichiometry.…”