Effect of doping by low concentration of iron on magnetic and structural properties of Bi2212

Superconducting Bi2Sr2CaCu2-xFexO8+δ ceramics samples (0 ⩽ x ⩽ 0.075) have been prepared in air by solid state reaction method. The structural, magnetic and superconducting properties of the samples have been analyzed by means of X ray powder diffraction (XRD), scanning electron microscopy (SEM) and AC susceptibility measurements. The increasing of Fe content shows an important decrease of the content of the Bi2212 phase while the Bi2201 parasitic phase content increases and the c lattice parameter is slightly reduced. The rate at which Tc is depressed by substitution by Fe is much lower than the one obtained by transport measurements made by other authors on single and whiskers crystals. The substitution by Fe increases also the broadening of the superconducting transition indicating an effect on the homogeneity of the samples.