High temperature electrical conductivity and Seebeck coefficient measurements were performed on the quadruple perovskites La2Ba2Cu2Sn2O11, Eu2Ba2Cu2Ti2O11, and La2Ba2Cu2Ti2O11. A transition from n- to p-type semiconductivity is observed for La2Ba2Cu2Sn2O11 as a function of oxygen partial pressure. However, both electrons and holes contribute to the electrical properties over the entire range of experimental conditions. Both Eu2Ba2Cu2Ti2O11 and La2Ba2Cu2Ti2O11 display p-type extrinsic semiconductivity at high oxygen partial pressures and low temperatures. A transition to lightly doped p-type, intrinsic semiconductivity occurs at low oxygen partial pressures and high temperatures. Combined conductivity and thermopower (Jonker) analysis was employed to elucidate the defect structure and the conduction parameters in these compounds. The similarity of these materials to high-Tc cuprates is discussed.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry