Most measurements of critical current densities in YBa2Cu3O7−δ thin films to date have been performed on films where the \textit{c}-axis is grown normal to the film surface. With such films, the analysis of the dependence of jc on the magnetic field angle is complex. The effects of extrinsic contributions to the angular field dependence of jc, such as the measurement geometry and disposition of pinning centres, are convoluted with those intrinsically due to the anisotropy of the material. As a consequence of this, it is difficult to distinguish between proposed FLL structure models on the basis of angular critical current density measurements on \textit{c}-axis films. Films grown on mis-cut (vicinal) substrates have a reduced measurement symmetry and thus provide a greater insight into the critical current anisotropy. In this paper previous descriptions of the magnetic field angle dependence of jc in YBa2Cu3O7−δ are reviewed. Measurements on YBa2Cu3O7−δ thin films grown on a range of vicinal substrates are presented and the results interpreted in terms of the structure and dimensionality of the FLL in YBa2Cu3O7−δ. There is strong evidence for a transition in the structure of the flux line lattice depending on magnetic field magnitude, orientation and temperature. As a consequence, a simple scaling law can not, by itself, describe the observed critical current anisotropy in YBa2Cu3O7−δ. The experimentally obtained jc(θ) behaviour of YBCO is successfully described in terms of a kinked vortex structure for fields applied near parallel to the \textit{a-b} planes.
@article{arxiv.cond-mat/0406620,
title = {Critical currents in vicinal YBa$_2$Cu$_3$O$_{7-\delta}$ films},
author = {J. H. Durrell and G. Burnell and Z. H. Barber and M. G. Blamire and J. E. Evetts},
journal= {arXiv preprint arXiv:cond-mat/0406620},
year = {2016}
}