High-temperature electrical conductivity and Seebeck coefficient measurements were performed on single-CuO2-layer La1-xSr1+x CuGaO5 (x = 0.1 and 0.13) and double-CuO2-layer Y1-xCaxSr2 Cu2GaO7 (x = 0, 0.1, 0.2, 0.4). The solubility range in Y1-xCaxSr2 Cu2GaO7 is most likely 0 ≤ x ≤ 0.2, whereas, only the x = 0.1 composition is stable in La1-xSr1+xCuGaO5. Carrier concentration is essentially independent of temperature and oxygen partial pressure in both systems. The defect structure is dominated by p = [AE′RE], where AE = alkaline earth and RE = La or Y. The conductivity, and therefore the mobility, is activated for x = 0 and x = 0.1 in Y1-xCaxSr2Cu2GaO7 . Solid solubility limits and charge localization play major roles in the establishment of superconductivity in these phases.
ASJC Scopus subject areas
- Materials Chemistry
- Physical and Theoretical Chemistry
- Inorganic Chemistry