Abstract
This work studied X-ray powder diffraction (XRD), electrical resistivity and electron paramagnetic resonance (EPR) measurements for Bi1.8Pb0.4Sr2Ca2.1Cu3-xRuxO10+delta (0.0 <= x <= 0.4) superconducting samples. XRD analysis and electrical resistivity data showed that the low-content of Ru, x <= 0.05, enhanced both the phase formation and the superconducting transition temperature of (Bi, Pb)-2223 phase. A phase change from (Bi, Pb)-2223 phase to (Bi, Pb)-2212 phase was reported for x >= 0.15. Two EPR lines were observed for 0.0 <= x <= 0.075, indicating the presence of both (Bi, Pb)-2223 and (Bi, Pb)-2212 phases. While, one EPR line was observed for x >= 0.15, corresponding to the (Bi, Pb)-2212 phase formation. The number of spins (N) participating in the resonance and its spin paramagnetic susceptibility (chi), for the two phases, were calculated as a function of both Ru-content and temperature. In addition, we reported the variation of activation energy (E-a), Curie constant (C), Curie temperature (theta) and effective magnetic moment (mu) with Ru-content. (C) 2011 Elsevier B.V. All rights reserved.