Influences of calcination temperature on growth and superconducting properties of GdBa2Cu3O7−δ films fabricated by fluorine-free metal organic deposition method

GdBa2Cu3O7−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 GdBa2Cu3O7−δ films were fabricated by fluorine-free metal organic deposition method via two different calcination temperatures, 723 K and 873 K, to examine the influence of calcination temperature on film growth and superconducting characteristics. Critical temperatures and critical current densities of the sample calcined at 873 K were superior to the sample calcined at 723 K. In the case of the sample calcined at 723 K, 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 873 K, 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.