Irreversibility Fields and Critical Current Densities in Strongly Pinned YBa2Cu3O7-x Films With Artificial Pinning Centers

We propose a microscopic approach to derive angular dependent critical current density J_c(θ) of YBCO films with c-axis correlated nanorods, based on the energy gain by pinning. Results are in good agreement with experimental ones. Irreversibility fields and J_c in YBa₂Cu₃O_7-x thin films containing segmented BaSnO₃ nanorods are systematically changed by selection of nanorod length and its spacing, and the variations are explained by the “harmonic oscillator” approach based on the Bose glass state. Analysis of pinning energies and J_c indicates that stacked BSO nanorod segments in line behave as single columnar with a smaller diameter pin for B|| c, in contrast, as nanoparticle pins for B||ab.