Influences of calcination temperature on growth and superconducting properties of GdBa₂Cu₃O_7-δ films fabricated by fluorine-free metal organic deposition method

GdBa₂Cu₃O_7-δ is one of the best candidates for the superconducting coated conductors because it has high critical temperature and high critical current density under high magnetic fields. In this study, superconducting GdBa₂Cu₃O_7-δ films were fabricated by fluorine-free metal organic deposition method via two different calcination temperatures, 723K and 873K, to examine the influence of calcination temperature on film growth and superconducting characteristics. Critical temperatures and critical current densities of the sample calcined at 873K were superior to the sample calcined at 723K. In the case of the sample calcined at 723K, the mixture of amorphous and crystalline phases was observed, and that of a- and c-axis oriented grains after the crystallization. In the case of the sample calcined at 873K, the randomly oriented crystalline phases were observed, and the mixture of c-axis oriented grains and (Gd, Al)₂BaO₄ phase after the crystallization. These microstructural changes caused the differences in superconducting characteristics.