Formation of YBa₂Cu₃O(7-δ) superconducting films by electrodeposition

Superconducting thick films of Y-Ba-Cu-O have been prepared via an electrodeposition procedure of the constituent metals on metallic substrates (Cu, Ag) followed by an oxidative thermal treatment. The films were electrodeposited at a constant potential of -3.5 V (vs. Ag/AgCl) from a single electrolyte bath, which contains the nitrates of the cations in dimethyl sulfoxide. The initial state of the precursor film and the formation process of the final superconducting film have been followed by IR spectroscopy, thermogravimetric analysis, X-ray diffraction and scanning electron microscopy. In the precursor film, yttrium and copper are present as metals while barium forms a carbonate. Dimethyl sulfoxide (DMSO) is not inert under the experimental conditions and oxidises to the sulfone. The superconducting transition temperature (T(c)) of the final film was ≃92 K and the critical current density (J(c)) values were ≃9 500 A cm^-2 at 77 K and zero field, the highest so far obtained by electrodeposition.