Electrochemical deposition of Pb-DOPED Bi-Sr-Ca-CuO films

• Main Author: David, Melanie Y.
• Format: text
• Language: English
• Published: Animo Repository 2004
• Subjects: Electroplating; Superconductors; Semiconductor films; Physics
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/3200; https://animorepository.dlsu.edu.ph/context/etd_masteral/article/10038/viewcontent/CDTG003736_P.pdf
• Institution: De La Salle University

Pb-doped BSCCO superconducting films were prepared on Ag electrode in a three-electrode cell containing nitrates of Bi, Pb, Sr, Ca and Cu dissolved in DMSO (dimethyl sulfoxide). The nitrates were varied to obtain Bi2-xPbxSr2Ca2Cu3O10 (x = 0.2, 0.4, 0.6, 0.8). Pt was used as counter electrode and Ag/Ag+ as reference electrode. DC deposition was used with electrode potential of -3.5V for 30, 45, and 60 minutes. Heat treatment was done at 250 degrees Centigrade for 3 hours, 700 degrees Centigrade for 3 hours and 750 degrees Centigrade for 6 hours in oxygen-rich environment to allow solid state reaction to occur on the film. SEM analysis showed the formation of randomly oriented plate-like and bar-like structures which can be attributed to the low-Tc phase and high-Tc phase, respectively. These were observed in films prepared in 0.2 Pb concentration. Melted and step-like growths were found in films with 0.2 and 0.8 Pb concentrations. Pinholes, cracks and impurities were also present. Spaces between plate-like structures of the films became denser as the Pb concentration increased. Definite relationship between film thickness and deposition time could not be determined because of the falling off the films when they were being retrieved from the electrochemical cell. Films prepared with x = 0.4 content showed negative Pb. Some films exhibited 2212 and 2201 phases in varying composition. X-ray diffraction analysis showed a combination of 2201, 2212 and 2223. The highest number of 2223 peaks was found for x = 0.2 and x = 0.4. Electrical resistivity measurements indicated transition temperatures from 81K to 123K. Those that had 0.2 and 0.4 Pb concentrations had a single phase with Tc onset of 116K and 110K, respectively. Films with 0.6 Pb concentration had two-phase transitions, 80K and 123L, while 0.8 Pb concentration had 81K.