New 1222-Type Thallium-Indium Layered Cuprates (Tl, In)Sr2(Nd, Ce)2Cu2Oz and Their Superconductivity
Chin. Phys. Lett. 1993, 10 (1):
A new series of 1222-type thallium-indium layered cuprate compounds (Tl, In)Sr2(Nd, Ce)2Cu2Oz have been successfully synthesized in the pure or nearly pure form and identified by powder x-ray diffraction analyses. The structure of the compounds is directly related to that of Nb-1222 NbSr2(Nd, Ce)2Cu2Oz, with a tetragonal body-center lattice. The lattice parameters are a=3.85Å, c=29.56Å for (Tl0.7ln0.3)Srz(Nd0.5Ce0.5)2Cu2Oz, and a=3.85Å, c=29.28Å for lnSr2(Nd0.75Ce0.25)2Cu2Oz. Resistance measurements showed that (T11-xInx)Sr2(Nd0.75Ce0.25)2Cu2Oz(x ≤ 0.8) are superconducting with Tc(onset)=30-40K .