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.