Investigation of structural and electrical changes due to iron-doping on the calcium site of Bi2Sr2CaCu2O8+δ (Bi-2212) superconductor sedimentation films

Abstract

The effects on the lattice parameters and the critical temperature of Bi-2212 superconducting films upon iron doping on calcium site prepared by sedimentation melt quench has been investigated. The iron content was varied from x=0 to 0.2 on a nominal stoichiometry of Bi₂Sr₂Ca_1-xFe_xCu₂O_8+δ. The samples were characterized by X-ray powder diffraction analysis and resistance vs. temperature measurements using the standard four-point probe technique. It has been found out that at the doping concentration x=0.20, the iron atom can no longer be fully accommodated within the Bi-2212 superconductor system. Even though it doesn’t completely kill the superconductivity of the sample, at x=0.20 iron doping, the iron does lower the transition temperature at which the sample’s resistivity drops to a minimum.