Vortex pinning landscape in YBa2Cu3O7 films grown by hybrid liquid phase epitaxy

Abstract

The influence of film thickness and growth rate on the vortex pinning in hybridliquid phase epitaxy (HLPE) films was explored. Film growth rates as high as12 nm s−1 (0.7 µm min−1) producedhigh Jc films. Weak or no thickness dependence was found in films of thickness ranging from 0.4 to3 µm. Field and angular measurements of the critical current density(Jc) and the power-lawexponent (N) of the current–voltage curves were used to determine the nature of pinning. Films thinner than0.6 µm showed a higher density of correlated defects parallel to theab plane than thicker films. Using HLPE, it was possible to achieve very strong pinning in films∼3 µm thick, yielding criticalcurrents over 300 A cm−1 width atself-field, and as high as 35 A cm−1 width at μ0H = 3 T at T = 75.5 K. Decreasing the deposition rate allowed improving the high field performance,opening up the possibility to engineer the pinning landscape of the HLPE films.