High-Temperature Electrical Characterization of Ga-Based Layered Cuprates

✍ Scribed by G.W. Tomlins; N.-L. Jeon; T.O. Mason; D.A. Groenke; J.T. Vaughey; K.R. Poeppelmeier

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 334 KB
• Volume: 109
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1994.1112

✦ Synopsis

High-temperature electrical conductivity and Seebeck coefficient measurements were performed on single-CuO ({ }{2}-) layer (\mathrm{La}{1-x} \mathrm{Sr}{1+x}) (\mathrm{CuGaO}{5}(x=0.1) and 0.13()) and double-CuO (\mathrm{CuO}{2})-layer (\mathrm{Y}{1-x} \mathrm{Ca}{x} \mathrm{Sr}{2}) (\mathrm{Cu}{2} \mathrm{GaO}{7}(x=0,0.1,0.2,0.4)). The solubility range in (\mathrm{Y}{1-x} \mathrm{Ca}{x} \mathrm{Sr}{2}) (\mathrm{Cu}{2} \mathrm{GaO}{7}) is most likely (0 \leq x \leq 0.2), whereas, only the (x=0.1) composition is stable in (\mathrm{La}{1-x} \mathrm{Sr}{1+x} \mathrm{CuGaO}{5}). Carrier concentration is essentially independent of temperature and oxygen partial pressure in both systems. The defect structure is dominated by (p=) [ (\left.A E_{R E}^{\prime}\right]), where (A E=) alkaline earth and (R E=) La or Y. The conductivity, and therefore the mobility, is activated for (x=0) and (x=0.1) in (\mathrm{Y}{1-x} \mathrm{Ca}{x} \mathrm{Sr}{2} \mathrm{Cu}{2} \mathrm{GaO}_{7}). Solid solubility limits and charge localization play major roles in the establishment of superconductivity in these phases. 1994 Academic Press, Inc.