Identification of Intrinsic ab-Plane Pinning in<tex>$rm YBa_2rm Cu_3rm O_7$</tex>Thin Films and Coated Conductors

TLDR

The angular‑dependent critical current density Jc in YBa₂Cu₃O₇ films grown by pulsed laser deposition shows a sharp peak for magnetic fields near the ab plane, arising from intrinsic pinning combined with extended defects parallel to the planes. The authors analyze the temperature and field dependence of the peak’s height and width to separate intrinsic pinning from extended defects, and compare these results with coated conductors that have a higher density of ab‑oriented correlated defects. In single‑crystal films, the low‑field peak is mainly due to extended defects while the high‑field peak is dominated by intrinsic pinning, and the authors observe an inverse correlation between Jc and the I‑V power‑law exponent that appears only in the intrinsic‑pinning regime, offering an interpretation of its origin.

Abstract

The angular-dependent critical current density J/sub c/ in YBa/sub 2/Cu/sub 3/O/sub 7/ films grown by pulsed laser deposition exhibit a sharp peak for magnetic field orientations near the ab plane, which arises from the combined effects of intrinsic pinning and extended defects parallel to the planes. An analysis of the temperature and field dependence of the height and width of this peak allows us to distinguish both contributions. We find that, in a film on single crystal substrate, the peak at low fields is due primarily to the extended defects, but at high fields it is dominated by intrinsic pinning. We compare these results with those of coated conductors with a larger density of ab-oriented correlated defects. We show a novel effect consisting in an inverse correlation between J/sub c/ and the power law exponent (N) of the I-V curves that only occurs in the intrinsic-pinning dominated regime, and we present an interpretation of its origin.