SYNTHESIS OF NEW 1223-TYPE SUPERCONDUCTING LAYERED CUPRATE (Tl,Cr)Sr2Ca2Cu3O9

Abstract

A new 1223-type (Tl,Cr)-based superconducting layered cuprate ( Tl 1−x Cr x) Sr 2 Ca 2 Cu 3 O 9 with x = 0.25 or 0.50 has been successfully synthesized in the pure or nearly pure form and identified by powder X-ray diffraction analyses. An excessive quantity of thallium is necessary for the formation of the (Tl,Cr)-based 1223-type compound without any Ba. Resistance measurements showed that the new (Tl,Cr)-based 1223 cuprate exhibits Tc(onset) above 100 K and Tc(ρ = 0) of 94 K. Effects of the Cr amount and preparation conditions on the formation and superconductivity of the (Tl,Cr)-based 1223-type cuprate are discussed.