The Oxycarbonate Y1.6Ca0.4Ba4Cu5CO3O11, n = 2 Member of the "123"-Type Derivatives (Y1-xCax)nBa2nCu3n-1CO3O7n-3

✍ Scribed by M. Hervieu; Ph. Boullay; B. Domengès; A. Maignan; B. Raveau

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 394 KB
• Volume: 105
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1993.1219

✦ Synopsis

The exploration of the system (\mathrm{Y}-\mathrm{Ba}-\mathrm{Cu}-\mathrm{C}-\mathrm{O}), using high resolution electron microscopy, has allowed the oxycarbonate (\mathrm{Y}{1.6} \mathrm{Ca}{0.4} \mathrm{Ba}{4} \mathrm{Cu}{5} \mathrm{O}{11} \mathrm{CO}{3}) to be isolated. This 123 derivative phase is characterized by the superstructure (a \approx 2 a_{123}, b \approx b_{123}, c \approx 2 c_{123}). It corresponds to the ordered replacement of one chain of (\mathrm{CuO}{4}) square planar groups out of two by one row of carbonate groups, involving the formation of chains of (\mathrm{CuO}{5}) pyramids running along (\mathbf{b}). This oxide, which is the first one derived from the pure barium superconductor (\mathrm{Y}{1-x} \mathrm{Ca}{x} \mathrm{Ba}{2} \mathrm{Cu}{3} \mathrm{O}{7}), can be described as the (n=2) member of the 123-type derivatives with the generic formulation ( (\left.\mathrm{Y}{t-x} \mathrm{Ca}{4}\right){n} \mathrm{Ba}{2 n} \mathrm{Cu}{3 n-1} \mathrm{CO}{3} \mathrm{O}{7 n-3}). O1993 Academic Press. Inc.