The dependence on the oxygen concentration of normal and superconducting properties of ceramic samples of Pb2Sr2Y1-xCaxCu3O8+δ has been investigated in the composition range of 0≤x≤0.5 and 0≤δ<2. The superconductivity in each sample with different x is suppressed with increasing δ, which is in good correspondence to the increase in resistivity and Hall coefficient with increasing δ, but is contradictory to the speculation by Ohta and Maekawa [Phys. Rev. B41 (1990) 6524]. It is found from chemical analysis that holes introduced by the extra oxygen first enter the CuOδ layer and then the PbO layer rather than the pyramidal CuO2 layer. With increasing δ, a structural phase transition from the orthorhombic phase to the tetragonal phase is observed at δ∼1 in every sample with different x. The dependence on the oxygen concentration of the magnetic susceptibility is also reported.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering