Observation of Anomalous Reentrant Superconductivity in Gd added Bi-2223 Superconductor

We report the observation of an anomalous reentrant superconducting-normal resistive transition behaviour in Gd added Bi$_{1.8}$Pb$_{0.35}$Sr$_{1.9}$Ca$_{2.1}$Cu$_{3}$Gd$_{x}$O$_{y}$ superconductor with x=0, 0.1, 0.2, 0.3, 0.4 and 0.5. The resistive transitions of the samples are measured by four probe contact method under different magnetic fields. Zhao et. al. [1] first observed this behaviour in Bi-2212/2223 intergrowth single crystals. This is interpreted using a model where Josephson coupling between the CuO2 trilayers is weakened by thermally activated resistance. Similar observations are made in the literature [2], [3]. Possible physical origins of this anomalous phenomenon are discussed. \\[4pt] [1] Zhao Y. , et. al. , Physical Review \textbf{B} 51, 3134 (1995) \\[0pt] [2] Wang W. , et al. , Physica \textbf{C} 341-348, 1921 (2000) \\[0pt] [3] Kim D. C., et al., Physical Review \textbf{B} 64, 064502 (2001)