We have fabricated Ce 2 mol% doped GdBa₂Cu₃O_y (Gd123) thin films on LaAlO3 substrates by FF-MOD to introduce the perovskite nanostructure of BaCeO₃ as effective artificial pins into the films. By manipulating the thickness of the film layer, the size and density of the artificial pins were controlled, and the effect on the critical current densities was investigated. Three-layer film with a thickness of 100 nanometers each achieved the critical current densities of 1.03 MA cm^-2 under 0 T, and 0.06 MA cm^-2 under 1 T. On the other hand, five-layer film with a thickness of 60 nanometers each achieved the critical current densities of 1.74 MA cm^-2 under 0 T, and 0.20 MA cm^-2 under 1 T. Therefore, it was found that as the layer thickness was thinner, the critical current densities increased. This result suggests that the size of the introduced artificial pins is limited by the film thickness, and then the pin density increased.

Keywords: GdBa2Cu3Oy, BaCeO3, MOD method, FF-MOD