Flux Pinning Properties and Microstructure in Films With Nanorods Fabricated by Vapor-Liquid-Solid Growth Technique

For an improvement of Jc under applied magnetic fields, an addition of BaZrO₃ (BZO) nanorods into REBa₂Cu₃O_y(REBCO) films is actively discussed. However, the growth mechanisms of the BZO nanorods are still evidently unexplained. In this study, in order to control the growth of BZO nanorods in REBCO films, we fabricated the Sm_1+xBa_2-xCu₃O_y (SmBCO) films containing BZO by conventional pulsed laser deposition (PLD-Sm+BZO) and vapor-liquid-solid technique (VLS-Sm+BZO). The self field Jc's of PLD- and VLS-Sm+BZO films showed 1.3 MA/cm² and 1.2 MA/cm², respectively. However, magnetic field dependence of the Jc for the VLS-Sm+BZO film was twice as high as that of the PLD-Sm+BZO film at 77 K, B = 5 T. From a microstructure analysis, we found the BZO nanorods in VLS-Sm+BZO film grew nearly straight along the c-axis of the SmBCO.