Enhanced flux pinning in YGdBCO film grown by sol–gel approach

Chemical Solution Deposition of YBCO Films with Gd Excess

“…Figure 6a shows the HAADF STEM overview of the YBCO-Gd 5% layer on the STO substrate. No precipitate particles or secondary phases ascribable to RE 2 O 3 were present, in contrast with the previously reported study by [20]. The vertical brighter/darker contrast corresponded to YBCO twin grains with an average size of 18.5 nm in [100]/[010]YBCO projection (giving ~13 nm in [110]YBCO projection).…”

“…Li et al observed an increase in both T c and J c in the whole field range at 77 K. These authors ascribed the enhancement to the significant presence of RE 2 O 3 phases in their films. In our work, instead, we observed a different behavior: T c was not affected by Gd addition (Table 4), whereas J c behaviors were more markedly improved at lower temperatures rather than at 77 K. This result, in agreement with the structural and morphological characterizations, evidenced the effect of the different nature of the introduced defects (no RE 2 O 3 phases were recognized in our samples), likely due to the different growth methods [20].…”

“…It is now worth drawing some remarks, even taking into account the results reported by previous work on a similar system, i.e., the addition of 10 mol % Gd to YBCO film by the sol-gel method [20]. Li et al observed an increase in both T c and J c in the whole field range at 77 K. These authors ascribed the enhancement to the significant presence of RE 2 O 3 phases in their films.…”

“…To our knowledge, the addition of Gd in stoichiometric excess with respect to Y, Y 1 Gd y Ba 2 Cu 3 O 7−δ, has been reported only by two papers: Xu et al [19] studied the Gd 2 O 3 introduction in YBCO bulk, and Li et al [20] grew, through a sol-gel process, YBCO films doped with Gd 10 and 50 mol %. These articles have shown promising results with enhanced critical current density (J c ) in both self-field and in-field conditions at 65 and 77 K, respectively.…”