Physica C 209 ( 1993) 5 16-5 I8 North-Holland The synthesis and superconductivity of a new type of Bi- 12 12 phase (Bi, Cd)Sr,(Y, Ca)Cu20, Qian Yitai, Tang Kaibin, Yang Peidong, Chen Zuyao and Li Rukang Department ofApplied Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China Zhou Guien and Zhang Yuheng Structure Research Laboratory, University of Science and Technology of China, Academia Sinica, Hefei. Anhui 230026, China Wang Nanlin Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China Received 26 January 1993 A novel series of Bi-1212 superconducting cuprates (Bi, _,Cd,)Sr,(Y,_,Ca,)Cu20. has been discovered in this work. The structure was suggested to be that of (Bi, Cu)Sr,YCu,O, with Cd*+ ions substituting into the Cu*+ Sites in the rock-salt-type (Bi, Cu)O layers. The superconductivity was induced in the as-prepared samples by treatment under oxygen pressure of 10 atm at 800°C with a composition of (Bi0.27Cdo.73)SrZ(Y0.7C~.3)Cu20r. The zero-resistivity temperature is 26 K. 1. Introduction Since the discovery of the Bi-Sr-Cu-0 system [ 11, a family of Bi-based superconducting cuprates BizSrzCa,_ 1C~,,02n+4( n = 1, 2, 3) has been formed [2,3]. These cuprates can be described as inter- growths of BizOz double layers with oxygen-deficient perovskite slabs. However, Bi-cuprates with a BiO monolayer had not been discovered. One of the most interesting focuses is whether the cuprates with a BiO monolayer could be formed. Recently, A. Ehmann et al. [ 41 reported a new family of superconducting cu- prates ( Bio,SCuo.s)Sr2YCua0, (Bi-1212). Its struc- ture is similar to that of (Pb, Cu)Sr,(Y, Ca)Cu*O, [ 5,6] (fig. I), in which Cu2+ ions need to partially substitute Bi3+ ions in the BiO monolayer in order to form the Bi-1212 phase. The Cd’+ ion is particularly interesting for inves- tigation owing to its position in the periodic table, ionic size and intrinsic chemical reactivity. Many works on Cd’+ doping have been reported [ 7-9 1. With Cd2+ partial substitution, Parise et al. [ lo] have investigated (T1,.,sCdo.25)Ba2Cu06+6 and T.P. a Bi,c!u 0 Sr zyxwvutsrqponmlkjihgfe or ecu 00 ,Cd Fig. 1. The schematic structure of (Bi, Cd)SrzYCuzO, Beales et al. [Ill have prepared (Pbo.sCdo.s)Sr2(Y0.7Ca,,3)Cu20, the superconduct- ing temperature of which is up to 92 K. In these two systems, Cd2+ ions mainly substitute within the rock- salt-type layers incorporating T13+ or Pb4+. In this work, we successfully prepared a new type of Bi-1212 cuprate, (Bi, Cd)Sr2(Y, Ca)Cu20,, and superconductivity has been induced in this system. 2. Experimental Samples with nominal compositions of 0921-4534/93/$06.00 0 1993 Elsevier Science Publishers B.V. All rights reserved.