| Summary: | This paper reports on the results of Yb substitution for Ca on the superconductivity and structural properties of Bi1.6Pb0.4Sr2Ca2-xYbxCu3Oy superconducting samples with x = 0.000, 0.025, 0.050, 0.100 and 0.200 which prepared by coprecipitation (COP) method. The samples were characterized by X-ray diffraction (XRD), field-emission scanning electron (FESEM), electrical and resistivity measurement by four-probe method. It was found that the substitution of Yb decreased the critical temperature (Tc zero), critical current density (Jc) and volume fraction of Bi-2223 phase. The samples have Tc zero in the range 77 to 100 K. Tc zero gradually decreased with an increase in Yb concentration, corresponding to small change of the carrier concentration. Jc was measured to be 5.7512 A/cm2M.m for pure sample and decreased to 4.1910 A/cm2 for x = 0.025 at 77 K. The crystallographic structure was found to change slightly from tetragonal to orthorhombic in Yb substituted samples. The lattice parameter c of Yb samples decreased due to the incorporation of Yb3+ (0.858 Å) with smaller ionic size compare to Ca2+ (0.99 Å). From the SEM observation, the grain connectivity became weak with smaller plate-like grain for x > 0.025 Yb concentration resulting in the decreased of Jc. © (2013) Trans Tech Publications, Switzerland.
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