J Mater Sci Technol ›› 2012, Vol. 28 ›› Issue (2): 169-176.

• Regular Papers • Previous Articles     Next Articles

Thermomechanical Analysis of (Cu0.5Tl0.5)-1223 Substituted by Pr and La

A.I. Abou Aly1), R. Awad1), I.H. Ibrahim1), M. Kamal2), M. Anas1)   

  1. 1) Physics Department, Faculty of Science, Alexandria University, Egypt
    2) Physics Department, Faculty of Science, Mansoura University, Egypt
  • Received:2011-04-06 Revised:2011-08-24 Online:2012-02-28 Published:2012-02-24
  • Contact: R. Awad

Abstract: The thermomechanical analysis (TMA) of Cu0.5Tl0.5Ba2Ca2-xRxCu3O10-δ, where R=Pr and La, with 0.0≤x≤0.15, was carried out in temperature range from 450 to 1145 K. The samples were prepared by single-step solid state reaction technique. The prepared samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The superconductivity of the prepared samples was investigated by electrical resistivity measurement. The results showed that low substitution content enhanced the (Cu0.5Tl0.5)-1223 phase formation, while the higher substitution content degraded this phase. The higher superconducting transition temperatures Tc were found to be 114 K and 109 K at x= 0.025 for Pr- and La-substitutions, respectively. The average linear thermal expansion coefficient increased as x increased, while the shrinkage temperature decreased as x increased. Those results were emphasized by porosity and Vickers microhardness calculations. Debye temperature θD was calculated from the linear thermal expansion coefficient data and correlated to Tc to estimate the electron-phonon coupling λep.

Key words: (Cu0.5Tl0.5)-1223, Thermomechanical analysis, Thermal expansion coefficient, Debye temperature