Strong enhancement of flux pinning in YBa2Cu3O7-delta multilayers with columnar defects comprised of self-assembled BaZrO3 nanodots

Multilayer structures comprising YBa2Cu3O7-delta (YBCO) films with columns of self-assembled BaZrO3 (BZO) nanodots with interlayers of CeO2 or pure YBa2Cu3O7-delta were grown on rolling-assisted biaxially textured substrates (RABiTSs) using pulsed laser deposition. A significant enhancement of the critical current density (J(c)) was observed for the multilayers compared with a single layer of YBCO + BZO. J(c) varies as J(c) similar to H-alpha with alpha of 0.27 for single layer of YBCO + BZO and 0.34 for both multilayered films. Enhancement of pinning in the multilayers is attributed to the presence of columnar defects comprised of self-assembled nanodots of BZO as well as planar CuO-type stacking defects arising as a result of interfacial reactions in the multilayers.