Large pinning forces and matching effects in YBa2Cu3O(7-δ) thin films with Ba2Y(Nb/Ta)O6 nano-precipitates

• Published in: Scientific reports Vol. 6; p. 21188
• Main Authors: Opherden, Lars, Sieger, Max, Pahlke, Patrick, Hühne, Ruben, Schultz, Ludwig, Meledin, Alexander, Van Tendeloo, Gustaaf, Nast, Rainer, Holzapfel, Bernhard, Bianchetti, Marco, MacManus-Driscoll, Judith L, Hänisch, Jens
• Format: Journal Article
• Language: English
• Published: England 18.02.2016
• ISSN: 2045-2322
• DOI: 10.1038/srep21188

The addition of mixed double perovskite Ba2Y(Nb/Ta)O6 (BYNTO) to YBa2Cu3O(7-δ) (YBCO) thin films leads to a large improvement of the in-field current carrying capability. For low deposition rates, BYNTO grows as well-oriented, densely distributed nanocolumns. We achieved a pinning force density of 25 GN/m(3) at 77 K at a matching field of 2.3 T, which is among the highest values reported for YBCO. The anisotropy of the critical current density shows a complex behavior whereby additional maxima are developed at field dependent angles. This is caused by a matching effect of the magnetic fields c-axis component. The exponent N of the current-voltage characteristics (inversely proportional to the creep rate S) allows the depinning mechanism to be determined. It changes from a double-kink excitation below the matching field to pinning-potential-determined creep above it.