Experimental Study of superconducting properties of HTS Bi2223superconductors with and without Doping

Abstract

In this paper work has been under taken aiming at investigating influence and Effects of chemical doping
on the surface morphology and superconducting properties of Bi2223 were studied in detail. Thin films of well-known
HTS (Bi2Sr2Ca2Cu3O10 (Bi-2223) and (Bi1.65-xPb0.35 Nbx)Sr2Ca2Cu3Oy(X =0.00, 0.01, 0.02) series were deposited by
electron beam evaporation method. The room temperature resistances of the Bi-2223 films were measured using
multimeter and it shows higher values of resistances. Surface reconstruction and remarkable decrease in the normal
state resistance were seen after ex-situ annealing. The low temperature resistance measurement for finding the critical
temperature (Tc) gave no results up to the LN2 temperature. Surface characterization of the films shows good surface
morphology with uniform Nano pillars formation. A clear grain growth with the annealing is evident. The average
particle size after annealing in the range ~ 120 -130 nm. Superconducting properties of the samples were investigated. In
(Bi1.65-xPb0.35 Nbx)Sr2Ca2Cu3Oy(X =0.00, 0.01, 0.02) series films DC electrical resistivity of all the samples decreased as
the wt% of Nb increased. Both the onset critical temperatures Tc (onset) and zero electrical resistivity critical
temperatures Tc (R = 0) of the samples were determined from the DC electrical resistivity measurements.