Preparation of Superconducting Ba₂YCu₃O_7-δ Thin Films by the Dipping-Pyrolysis Process Using Metal Naphthenates and Acetylacetonates

Abstract

Thin films of superconductor Ba₂YCu₃O_7-δ (BYCO) were prepared on the yttria-stabilized zirconia substrates by the dipping-pyrolysis process using metal naphthenates and acetylacetonates as starting materials. Barium, yttrium and copper naphthenates and acetylacetonates, with molar ratios of (A) Ba:Y:Cu=2:1:3 and (B) 3:1:4.3, were dissolved in toluene and a mixture of pyridine and propionic acid, respectively, to make homogeneous solutions. After dipping, drying and preheating at 500°C were repeated 10-20 times, final heat treatment at 950°-970°C in O₂ gave 5-10μm thick BYCO films, which showed superconduction at T_{c, zero} of 89-91K. Results of scanning electron microscopy and X-ray diffraction analysis showed dense textures of orthorhombic BYCO grains.