The incorporation of nanoscale columnar defects comprised of self-assembled BaZrO3 nanodots to improve the flux pinning and critical current density of NdBa2Cu3O7-δ films grown on RABiTS

We report significant enhancement in the flux-pinning of epitaxial NdBa2Cu3O7-delta (NdBCO) films on rolling-assisted biaxially textured substrates (RABiTS) via the incorporation of a two-dimensional array of columnar defects comprised of self-assembled BaZrO3 (BZO) nanodots. Pure NdBCO films and NdBCO films incorporating BZO nanodots, both with the same thickness of 0.6 mu m, were epitaxially grown on RABiTS by pulsed laser deposition. A very dense and homogeneous distribution of BZO nanodot columns with typical intercolumn spacing of around 15-20 nm oriented along the c-axis of the film was observed in the NdBCO + BZO film. Compared to the pure NBCO film on RABiTS, the NdBCO + BZO film on RABiTS has an in-field critical current density (J(c)) of a factor of more than 2 in 0.1-1.5 T and a smaller power-law exponent alpha similar to 0.21 in the field regime where J(c) similar to H-alpha.