YBACUO AND TLBACACUO SUPERCONDUCTOR THIN-FILMS VIA AN ELECTRODEPOSITION PROCESS

Thin-film superconductors of YBaCuO (YBCO) and TlBaCaCuO (TBCCO) were fabricated via an electrodeposition process. The YBCO superconductor precursor thin films were deposited at potentials ranging from -2.5 to -4 V vs. an Ag/AgNO3 reference electrode. The YBCO films were deposited under both constant and pulsed-potential conditions. The post-annealed YBCO films showed zero resistance of approximately 74 K on Ni, 78 K on MgO, and 91 K on ZrO2 substrates. The best critical current densities obtained for the YBCO films at 4 K and zero magnetic field and their respective substrates are as follows: 4000 A/cm2 on [100] ZrO2, 3960 A/CM2 on [100] MgO (constant potential), 5160 A/cm2 on [100] MgO (pulsed potential), 500 A/cm2 on a Ni strip, 325 A/cm2 on a Ni wire, and 500 A/cm2 on a Ag wire. The precursors of the super-conducting conducting TBCCO films were codeposited at a constant potential of -4 V and also under pulsed-potential conditions. The post-annealed TBCCO films showed zero resistance at about 102 K on SrTiO3 substrate. The critical current density at 76 K of a TBCCO film deposited at constant potential on a silver-coated SrTiO3 substrate was 20,000 A/cm2 in zero magnetic field and 5,000 A/cm2 in a 10 kOe field parallel to the film plane. The critical current density of pulsed-potential deposited TBCCO film on SrTiO3 was 56,000 A/cm2 at 76 K in zero field.