Preparation of Superconducting Ba2YCu3O7-δ Films by the Dipping-Pyrolysis Process Using Metal Laurates

Abstract

Superconducting Ba2YCu3O7-δ (BYCO) films were prepared on the yttria-stabilized zirconia substrates by the dipping-pyrolysis process using metal laurates as starting materials. Propionic acid and pyridine were selected as solvents based on the screening test on solubility of each of Ba-, Y- and Cu-laurates in 26 organic liquids with various functional groups. A homogeneous solution of mixed laurates (Ba:Y:Cu=2:1:3) was prepared by using a mixture of propionic acid and pyridine. This solution was spin-coated on the YSZ substrates and preheated at 500°C in air to make (BaCO3-Y2O3-CuO) precursor films. After this procedure was repeated 15 times, the precursor films were heat-treated at 925°-970°C in O2 to give 2μm thick BYCO films, which showed superconduction at Tc, zero of 69-84K. Observation with a scanning electron microscope and X-ray diffraction analysis showed dense textures of orthorhombic BYCO grains.