# Superconducting bismuth and thallium cuprates of the type $Bi_{2-x}Pb_x(Ca,Sr,Y)_{n+1}Cu_nO_{2n+4+\delta} (Tl,Pb)(Ca,Ln)(Sr,Ba)_2Cu_2O_{6+\delta}$ and $Tl(Sr,Ln)_{n+1}Cu_nO_{2n+3+\delta}$

Rao, CNR (1991) Superconducting bismuth and thallium cuprates of the type $Bi_{2-x}Pb_x(Ca,Sr,Y)_{n+1}Cu_nO_{2n+4+\delta} (Tl,Pb)(Ca,Ln)(Sr,Ba)_2Cu_2O_{6+\delta}$ and $Tl(Sr,Ln)_{n+1}Cu_nO_{2n+3+\delta}$. In: Diffusion and Defect Data - Solid State Data, Part A (Defect and Diffusion Forum), 2-3 Oct. 1989, Indianapolis, IN, USA, pp. 1-18.

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## Abstract

In the $Bi_{2-x}Pbx(Ca,Sr)_{n+1}Cu_nO_{2n+4+\delta}$ system, the superconducting properties of the n=1 to 4 members was established. The $T_c$ in this system increases from n=1 to 3 and does not increase further when n=4. In oxygen-annealed $Bi_2Ca_{1-x} Y_xSr_2Cu_2O_y$, the $T_c$ decreases with increase in x; in samples prepared in air or in a $N_2$ atmosphere, there is an increase in $T_c$ with x up to 0.25. Such electron-induced enhancement of $T_c$ is of interest. In $TlCa_{1-x}Ln_xSr_2Cu_2O_{6+\delta}$, electron- or hole-superconductivity was found to depend on x. $TI_{1-x}Pb_xCaSr_2Cu_2O_{6+\delta}$ shows clear evidence of electron superconductivity. $Tl(Sr,Ln)_{n+1}Cu_nO_{5+\delta}$ (n=1 and 2) superconductors containing neither Ca nor Ba have been characterized for the first time.

Item Type: Conference Paper Copyright of this article belongs to Trans Tech Publications Inc.. bismuth compounds;calcium compounds;high-temperature superconductors;lead compounds;rare earth compounds; strontium compounds;superconducting transition temperature; thallium compounds Division of Chemical Sciences > Solid State & Structural Chemistry Unit 16 Jan 2008 12 Jan 2012 08:16 http://eprints.iisc.ernet.in/id/eprint/11158