High in-field critical current densities in epitaxial NdBa ₂Cu₃O_7-δ films on RABiTS by pulsed laser deposition

We report the epitaxial growth and superconducting properties for NdBa ₂Cu₃O_7-δ (NdBCO) films grown on rolling-assisted, biaxially-textured substrates (RABiTS) by pulsed laser deposition. At the optimum deposition temperature of 760 °C, the critical current densities, J_c, at 77K, self-field, of NdBCO films ranging in thickness from 0.13 to 0.25νm were found to be in the range 2.2-3.4MAcm ^-2, with a lower thickness corresponding to a higher J_c. Compared to epitaxial YBa₂Cu₃O_7-δ (YBCO) films, these NdBCO samples are found to have superior field and angular dependences of J_c. In an applied field of 1T, NdBCO of the same thickness has more than twice the J_c of YBCO films with a significantly enhanced J_c peak for a field applied parallel to the c-axis. These results suggest the presence of an increased density of c-axis correlated pinning centres within NdBCO films compared to YBCO films.