Superconductivity oxides exhibiting

The superconductive oxides Pb2Sr2Ca1 xYxCu308 (36) and Pb2.xBixSr2Cai yYyCu308 (37) which exhibit a zero resistance at temperatures ranging from 46K to 79K respectively do not seem to... 

As shown in table 1, most of these oxides exhibit superconducting properties, with critical temperatures ranging from 10 K to 125 K. However the critical temperature may vary dramatically with the stoichiometry of the phase as will be discussed fur ier. 

The observed disappearance of electrical resistance when mercury and a few other alloys were cooled at liquid He temperature, led to die term superconductors. Only in 1986 did an oxide exhibit superconductivity and at higher transition temperatures, T. The following year the ceramic oxide YB2Cu307. (or YBCO) was found to become superconductor at a temperature >77 K (the boiling point of nitrogen). The ease of its preparation and its study makes it an interesting material. 

Because of the variety of structures and chemical compositions, perovskite oxides exhibit a large variety of properties. Well-known properties of the perovskite oxides are ferroelectricity in BaTiOs-based oxides and superconductivity in Ba2YCu307, etc. In addition to these well-known properties, several perovskite oxides exhibit good electrical conductivity, which is are close to that of metals, and ionic conductivity, as well as mixed ionic and electronic conductivity. Based on these variations in electrical conducting property, perovskite oxides are chosen as the components for SOFC. It is also well known that several perovskite oxides exhibit high catalytic activity with respect to various reactions, in particular, oxidation reactions [10]. Table 1.2 provides examples of the typical properties of perovskite oxides. In this section, several typical properties of the perovskite oxides, namely, ferroelectricity, magnetism, superconductivity, and catalytic activity, are briefly discussed. 

Electrical and Electronic Applications. Silver neodecanoate [62804-19-7] has been used in the preparation of a capacitor-end termination composition (110), lead and stannous neodecanoate have been used in circuit-board fabrication (111), and stannous neodecanoate has been used to form patterned semiconductive tin oxide films (112). The silver salt has also been used in the preparation of ceramic superconductors (113). Neodecanoate salts of barium, copper, yttrium, and europium have been used to prepare superconducting films and patterned thin-fHm superconductors. To prepare these materials, the metal salts are deposited on a substrate, then decomposed by heat to give the thin film (114—116) or by a focused beam (electron, ion, or laser) to give the patterned thin film (117,118). The resulting films exhibit superconductivity above Hquid nitrogen temperatures. 

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