Determination of the Critical Current Density in $\hbox{YBa}_{2}\hbox{Cu}_{3}\hbox{O}_{7-\delta}$ Thin Films Measured by the Screening Technique Under Two Criteria

We report the determination of critical current density J c flowing in YBa 2 Cu 3 O 7-δ superconducting thin films by two independent criteria. The estimation of J c was carried out by an inductive technique, i.e., the so-called screening technique. Both the imaginary part of the fundamental harmonic of susceptibility χ 1 " and the third harmonic of the voltage V 3 criteria were used to determine the full penetration field. Our goal is to shed light on the selection of the criterion for the determination of J c . In order to compare the inductive criteria, we investigated the homogeneity of J c via transport measurements conducted on microbridges patterned in the films. Based on the transport method, we found that, for temperatures close to critical temperature T c , both techniques yield similar results in the determination of J c . However, at temperatures relatively far from T c , the V 3 criterion showed better agreement with the transport data. Furthermore, using both criteria, we propose an alternative methodology to estimate in situ the coil factor associated with the V 3 criterion, avoiding in this way the need for implementing an additional technique.