Metallooxide superconductor BaPb1-xBixO3: unusual properties and new applications

The review of experimental and theoretical investigations of the superconducting solid solutions BaPb2-xBixO3 (BPB) with the critical temperature Tc <or approx. 13 K is given. The crystal structure, structural phase transitions, electrical and optical properties are discussed. The theory of superconductors with a partial dielectrization of the electron spectrum is used to explain the heat capacity and the upper critical field measurements. Much attention is paid to the granular macrostructure of ceramics and the Josephson intergranular weak links. The correlations between dependences of the normal and superconducting properties on the composition of BPB are elucidated. The nature of the superconducting high Tc state with a small electron density of states at the Fermi surface V(O)=3x1021 eV-1cm-3 is discussed