Highly enhanced superconducting properties of Eu-doped (Bi,Pb)-2212

The structural and superconducting properties of Eu-doped (Bi,Pb)-2212 superconductor have been studied. Eu concentration is varied from x = 0.0 to 0.4 in a general stoichiometry of Bi1.6Pb0.5Sr2−xEuxCa1.1Cu2.1Oy. It is found that the Eu atoms enter into the crystal structure by replacing Sr atoms and induce significant changes in lattice parameters, microstructure, hole-concentration and normal-state conductivity of the system. The critical temperature (TC) and critical current density (JC) at self-field of the Eu-doped samples enhanced considerably for optimum doping levels. Maximum TC-onset of 95.7 K (for x = 0.2) and JC of 1196 A/cm2 at 64 K (for x = 0.1) were observed for doped samples as against 79.8 K and 105 A/cm2, respectively, for the pure sample. The results are discussed on the basis of the changes in hole-concentration due to Eu-doping.