Relationship between critical current properties and nanorod morphology in REBa₂Cu₃O_y, thin films

Changes in critical current properties depending on growth temperature (T_s) were clarified for Ba-Nb-O-doped YBa₂Cu₃O_y (Y123) films deposited by YAG- and excimer-PLD. Due to the introduction of Ba-Nb-O-nanorods, a vortex-Bose-glass-like behavior emerged as irreversibility lines and in-field critical current densities (J_cs) were improved. Crossover magnetic fields (B_cr) and in-field J_cs increased with the increase in T_s for the Y123 films with nanorods. These T_s-dependent critical current properties were attributable to the changes in morphology of the nanorods with T_s and were independent of laser source in PLD apparatuses. For the fabrication of RE123 coated conductors containing nanorods, optimization of T_s with taking both materials of RE123 matrix and nanorod into account is necessary to achieve higher in-field J_c.