Enhancement of critical current density and flux pinning properties of Gd-doped (Bi, Pb)-2212 superconductor

Abstract

The enhanced critical current density (JC) and flux pinning properties of Bi1.7Pb0.4Sr2-xGdxCa1.1Cu2.1O8+δ (where x=0.0, 0.1, 0.2, and 0.3) system prepared by solid-state synthesis in bulk polycrystalline form were studied. Phase analysis, microstructural investigation, and superconducting characterization were performed to evaluate the relative performance of the samples. The x-ray diffraction and energy dispersive spectroscopy analyses show that Gd atoms are successfully doped in place of Sr in the system. It is found that Gd in (Bi, Pb)-2212 enhances the critical temperature (TC), JC, and flux pinning strength of the system. The flux pinning force (FP) calculated from the field dependant JC values shows that the irreversibility line of the Gd-doped (Bi, Pb)-2212 shift toward higher fields to different extents depending on the value of x. The samples with x=0.2 show maximum FP of 645 kN m−3 and the peak position of FP shifts to higher fields (0.68 T) as against 26 kN m−3 and 0.12 T for the pure sample. Also, the values of self-field JC and pinning potential (U0) are maximum for this sample (x=0.2). The enhancements of TC, self-field JC, JC(B) characteristics, U0, and FP are explained on the basis of the hole optimization and formation of point defects due to the doping of Gd in (Bi, Pb)-2212 system.

Vickers hardness measurements and some physical properties of Pr2O3 doped Bi-2212 superconductors

“…Further, although the Bi-2212 materials play an important role on the preparation of long wires and tapes, the applications of them in magnetic field and high temperatures are reported to limit because of their structural layer, very low charge carrier density, strong anisotropic properties, extremely short coherence length (n) and large penetration depth (k) [16,18]. Similarly, the Bi-2212 superconductors have relatively poor mechanical properties, limiting the use of these materials in most of practical applications [19]. Hence, several methods have been studied to improve these properties of the materials for years.…”

Infield response of (Al2O3)x/CuTl-1223 nanoparticles-superconductor composites

“…Resistive dissipation causes a variety of problems, which include reduced efficiency of transmission lines, and noise in superconductivity based devices. At low temperatures and currents, the inhomogenities, dislocations, grain-boundaries and rough surfaces are the sources of intrinsic pinning in a superconductor material [5][6][7][8][9]. This pinning locks the vortices in place and reduces the resistance.…”

Analysis of thermo-magnetic fluctuations in Bi1.6Pb0.5Sr2−xLuxCa1.1Cu2.1O8+δ (0.000≤x≤0.125) superconductor

“…Because the activation energy is the potential barrier height, it is the measure of flux pinning strength of the superconductor. In most of the existing reports, the activation energy is determined from the thermally assisted flux creep theory described by the Arrhenius equation [13,14] However, in HTS the increase in width of the resistive transition in magnetic field is a direct consequence of thermal fluctuations in the vortex system [8,11,12,15]. Hence one should consider both temperature and magnetic field dependent pinning analysis for a meaningful estimation of activation energy of the superconductor.…”

“…Also the Pb-substituted Bi-2212 [(Bi, Pb)-2212] has shown enhanced J C s in applied fields, compared to the Pb-free Bi-2212 [7]. Again a few studies reported that the flux pinning strength of (Bi, Pb)-2212 increases by rare-earth (RE) doping [8][9][10] and the flux pinning ability is usually determined from the values of flux pinning force density and activation energy [8,11,12]. Because the activation energy is the potential barrier height, it is the measure of flux pinning strength of the superconductor.…”