Superconducting coatings in the system Bi-Ca-Sr-Cu-O prepared by plasma spraying

Superconducting coatings in the system Bi-Ca-Sr-Cu-O were deposited on alumina substrates by plasma spray methods. The coatings were superconducting in the "as-sprayed" condition and improved with heat treatment. The best results were for coatings with resistivity values near 10 mΩ cm at room temperature and zero resistance at 96 K. The coatings had a magnetic transition near 80 K, with a weak diamagnetic signal up to 112 K. Superconductivity in the coatings was associated with two distinct phases, one of which was not identified. Scanning electron microscopy, x-ray diffraction, electrical resistivity, and magnetic measurements were used to characterize the coatings.