Long period mixed layer polytypes in the Tl2Ba2CanCu1+nO6+2n superconductors

✍ Scribed by G. Van Tendeloo; M. Verwerft; S. Amelinckx

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 92 KB
• Volume: 162-164
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(89)90536-4

✦ Synopsis

High Tc superconductors in the homologous series TI2-xBa2CanCul+nO6÷2n can exist up to at least n.,4. It is found furthermore by electron microscopy and electron diffraction that mixed layer polytypes with very large unit cells,up to several hundred AngstrOm occur. These large repeat units originate from a periodic mixture of compounds with n=4 and n=3 combined with the fact that both single and double TI-O layers may occur. The critical temperature is slightly affected by these modulations. Susceptibility measurements indicate a Tc of 117K is found; R=0 was obtained at 110K.