Strong flux-pinning in epitaxial NdBa2Cu3O7−δfilms with columnar defects comprised of self-assembled nanodots of BaZrO3

Epitaxial NdBa 2 Cu 3 O 7−δ (NdBCO) films with and without the incorporation of self-assembled nanodots of BaZrO 3 (BZO) were grown on rolling-assisted-biaxially-textured substrates (RABiTS) by pulsed laser deposition. Compared to epitaxial YBa 2 Cu 3 O 7−δ (YBCO) films on RABiTS, NdBCO films are found to have superior performance in applied fields at all field orientations, suggesting the presence of an increased density of pinning centres. The incorporation of columns of self-assembled nanodots of BZO within the NdBCO films results in further enhancement of the in-field J c at all field orientations. J c varies as J c ∼ H −α at intermediate fields, with α values for NdBCO and BZO-doped NdBCO films being ∼0.37 and ∼0.43, respectively, which are significantly lower than α∼0.52 for YBCO film.