Effect of Ba-Ca-Cu precursor matrix on the formation and properties of superconducting Tl2Ba2Can-1CunOx films - A combined metalorganic chemical vapour deposition and thallium vapour diffusion approach

Superconducting thin films of the Tl2Ba2CaCu2Ox (2212) and Tl2Ba2Ca2Cu3Ox (2223) phases have been prepared through a vapour diffusion. The effects due to the nature of the BaCaCuO(F) precursor matrix on the formation of the TlBaCaCuO phase film have been investigated. Fluorinated [BaCaCuO(F)] matrices have been deposited from Ba(hfa)(2) . tetraglyme, Ca(hfa)(2) . tetraglyme and Cu(acac)(2) via metalorganic chemical vapour dc position (MOCVD) on yttria-stabilized zirconia (YSZ) substrates. Both fluorinated [BaCaCuO(F)] and unfluorinated (BaCaCuO) matrices proved suitable for vapour diffusion thallium incorporation using selected Tl2O3:BaO:CaO:CuO mixtures. The formation of the superconducting 2212 and 2223 films is discussed depending upon the fluorinated and unfluorinated nature of the precursor matrices.