Electrodeposition and Characterization of Yttrium Barium Copper Oxide Superconducting Thin Films

Precursor thin films of Y-Ba-Cu-O superconductor were produced by potentiostatic and pulse electrodeposition from the dissolved nitrate salts of Y, Ba, Cu in dimethylformamide (DMF). The films were deposited on metal foils such as Ag-coated Cu, Ag, Ni, and Zr. Films were also synthesized on Ag-coated SrTiO_3, CaTiO _3, and Al_2O _3. The electrodeposited films were heat treated in flowing O_2 in order to produce the superconducting phase. The film composition as a function of the salt concentration in DMF was determined by energy dispersive x-ray analysis. Surface compositions were obtained by Auger electron spectroscopy. Crystal structure and phases were identified by means of x-ray diffraction. The superconducting dimagnetic behaviour has been observed in magnetic measurements. Films formed by pulse plating on the titanates and on Zr exhibited the best uniformity with highest T_{rm c}. Y-Ba-Cu-O films formed on Zr had highest T_{rm c} onset at 93 K (resistance measurement). The pulse plating process was extended to the synthesis of Er-Ba-Cu-O films. On Zr, the latter resulted in a T_{rm c} onset at 80 K.