Facile and efficient preparation of high-performance REBa2Cu3O7−x superconducting films through a novel fluorinated solution route

REBa2Cu3O7−x (RE = Y, Gd, Yb) superconducting films were prepared through an advanced low-fluorine solution route. The precursor solution was prepared using fluorine-free copper and barium salts, and fluorine-contained rare earth salts. Metal fluorides and oxides were formed as intermediate phases in the precursor films, which were pyrolyzed at 400–500 °C. After reacting with water gases during the firing process at 800 °C, the fluorides were transformed into the oxides, finally leading to the formation of superconducting REBa2Cu3O7−x (REBCO) phases. Due to the low-content of fluorine in the solution, high-rate production of REBCO films could be realized using this low-fluorine solution method. All the REBCO films had a good out-of-plane texture with a high critical transition temperature of more than 90 K and a critical current density of more than 2 MA/cm2.