The first superconducting thin film oxycarbonates coherent intergrowth of several members of a new structural series (CaCuO2)m (Ba2CuO2CO3)n

✍ Scribed by J.L. Allen; B. Mercey; W. Prellier; J.F. hamet; M. Hervieu; B. Raveau

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 776 KB
• Volume: 241
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(94)02356-5

✦ Synopsis

Superconducting thin films of copper oxycarbonates have been synthesized for the first time using laser ablation. The resistance measurements show a broad transition with Tc on~t ranging from 80 to 100 K and zero resistance below 60 K. Magnetic measurements indicate diamagnetism below 58 K in the best film. The ED and HREM studies show that these new oxycarbonates are tetragonal with a.~ ap and c ~ (m + 2 ) × ap, and that the films consist of an intergrowth of several members of a family with the general composition (CaCuO2)m (Ba2CuO2CO3)n. The main member that forms the matrix, Ba2Ca3Cu4CO3Os (m = 3; n = 1 ), consists of double layers of CuO4 groups sandwiched by pyramidal copper layers and interconnected with layers of CO3 groups. In a general way, the different members of the series can be described as the intercalation of layers of carbonate groups in the infinite-layer structure CaCuO2. The origin of superconductivity and the relationships with bulk "BaCaCu" oxycarbonates that are prepared at high pressure are discussed.