The effect of excess Ca2CuO3 on the superconducting properties of Bi1.7Pb0.3Sr2Ca2Cu3 Oy was investigated through X-ray diffraction (XRD), resistivity and a.c. magnetic susceptibility measurements. The XRD patterns revealed that 2223 is the major phase. The intensities of the peaks corresponding to Ca2CuO3 at 2θ=35.1 and 36.3, and those corresponding to the high Tc (2223) phase increased with increasing Ca2CuO3 concentration. The Tc(0) values, however, decreased with increasing Ca2CuO3 concentration. The real part of the a.c. susceptibility showed a two-step transition and two sets of peaks were observed in χ″ vs. T plots. The first set of peaks were approximately 10 K less than the Tc(0) values, whereas the second set of peaks occured in the temperature range 40-60 K. Both sets of peaks shifted towards lower temperatures with increasing Ca2CuO3 concentration. The role of Ca2CuO3 in the growth of 2223 phase and the mechanism of energy loss are discussed.
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