TITLE:
Investigation of Niobium (Nb) Substitution on Structural and Superconducting Properties of (Bi, Pb)-Based Superconductors
AUTHORS:
Reza Asghari, Hasan Sedghi, Leyla Çolakerol Arsalan, Hamid Naghshara
KEYWORDS:
H-T Superconductors, Bi-2223 Phase, Bi-2212 Phase, Bi-2201 Phase, X-Ray Diffraction
JOURNAL NAME:
Advances in Materials Physics and Chemistry,
Vol.7 No.7,
July
25,
2017
ABSTRACT: In this
study, the effects of Nb substitution on the Bi-based superconducting materials
have been investigated. The X-ray diffraction measurement indicated coexistence
of Bi-2212, Bi-2223 phases and some impurity phases of CuO, CuNb2O6,
CaNb2O6, CaCuO2, and Sr5Nb5O16.
With increasing Nb content, impurity phases consistent with the Nb element
appeared in the samples. Also with increasing Nb content, the Bi-2223 phase of samples gradually was decreased
and in contrast, the Bi-2212 phase was increased. From the SEM, results have been seen that with increasing of Nb
contents, the crystal structure of the samples was slightly changed because of
the disrupted grain growth. From the electrical resistivity measurements, it has been found that with increasing of Nb
contents, critical temperature decreases and the superconducting transition
width (ΔT) increases. Estimated
critical current density showed that Jc decreases with increasing Nb content, as expected.