Superconducting and normal state behaviors of (Tl, Bi)Sr2-xTixCa0.9Y0.1Cu2O7 ceramics

• Published in: Ceramics international 2004, Vol.30 (7), p.1591-1595
• Main Authors: YAHYA, A. K, ABDULLAH, W. F, JUMALI, M. H, IMAD, H, ABD-SHUKOR, R
• Format: Article
• Language: English
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; Chemical industry and chemicals; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cuprates superconductors (high tc and insulating parent compounds); Electrotechnical and electronic ceramics; Exact sciences and technology; High-Tc compounds; Other cuprates; Physics; Superconductivity; Technical ceramics
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2003.12.193

Effects of Bi and Ti substitutions at Tl and Sr sites, respectively, on superconducting and normal state behaviours of (Tl,Bi)Sr2-xTixCa0.9Y0.1Cu2O7 (x = 0-0.5) and Tl1-yBiySr1.9Ti0.1Ca0.9Y0.1Cu2O7 ceramics were investigated. Temperature-dependent resistance measurements on Tl0.9Bi0.1Sr2-xTixCa0.9Y0.1Cu2O7 (x = 0) showed metallic normal state behaviour with T(c onset) of 96 K and T(c zero) of 61 K. Substitution of Ti caused deterioration of superconductivity and gradual change of normal state resistance from metallic behaviour (x = 0-0.3) to semiconductor-like behaviour (x = 0.4-0.5). Resistance versus temperature measurements on Tl1-yBiySr1.9Ti0.1Ca0.9Y0.1Cu2O7 (y = 0-0.6) showed optimum superconductivity for y = 0.3 with T(c onset) of 98 K and T(c zero) of 68 K. The effects of Bi and Ti substitutions on superconducting and normal state behaviours of the ceramics are discussed in terms of ionic radius of elements and the concept of average Cu valence. 14 refs.