Flux pinning enhancement in YBa2Cu3O7-x films with BaSnO3 nanoparticles

Nanoparticles of BaSnO3 were incorporated into YBa2Cu3O7-x (YBCO) films on LaAlO3 substrates for magnetic flux pinning enhancements. More than an order of magnitude improvement in the high field magnetization J(c) at 6 T at 77 K was observed as compared to regular YBCO films. The irreversibility field (H-irr) was increased to 8.5 T at 77 K and to 13.4 T at 65 K. The in-field transport current measurements confirmed an order of magnitude improvement in high fields. The angular dependence of the Jc data at 1 T showed that J(c)H vertical bar vertical bar c is 1.3 times higher than J(c)H vertical bar vertical bar ab indicating the presence of c-axis correlated defects. Transmission electron microscopy studies revealed the presence of a large density of uniformly distributed similar to 10 nm sized BaSnO3 precipitates and strain fields around them. A dual sector pulsed laser deposition target is used to produce the films, thus eliminating reactions between BaSnO3 and YBCO during the target preparation stage, but may allow the BaSnO3 to react locally and create defects that act as pinning centres.