Organometallic chemical vapor deposition of superconducting, high T c Pb-doped Bi-Sr-Ca-Cu-O thin films

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Abstract
Highly oriented films of the high Tc Bi‐Pb‐Sr‐Ca‐Cu‐O (BPSCCO)superconductor have been prepared by two organometallic chemical vapor deposition (OMCVD) approaches. In the first approach, Pb is introduced by alternate deposition of BSCCO and PbOx films using the volatile metalorganic precursors Cu(acetylacetonate)2, Sr(dipivaloylmethanate)2, Ca(dipivaloylmethanate)2, triphenyl bismuth, and tetraphenyl lead. In the second approach, Pb is incorporated into an OMCVD‐derived BSCCO film by vapor diffusion using PbO as the source. X‐ray diffractometry and scanning electron microscopy reveal that Pb doping significantly improves the crystalline orientation and the film morphology. Films deposited by both methods on [100] single‐crystal MgO consist predominantly of the Bi2(Sr,Ca)3Cu2Ox phase and have a high preferential orientation of the crystallite c axes perpendicular to the substrate surface. Four‐probe resistivity measurements indicate the onset of film superconductivity at ∼110 K and zero resistance by 80 K.