Effects of Nb2O5 addition on the formation and properties of Bi-based superconductors

Ghazanfari, Nader
Effects of Nb2O5 addition on the formation and properties of the Bi-based superconductors were studied. The superconducting samples were synthesized by two different methods, the solid state reaction (SSR) and ammonium nitrate melt route (ANM) to obtain information about the growth techniques. Ten samples (five with each method) with the chemical compositions of Bi1.6Pb0.4Sr2Ca2Cu3NbxOy, with x= 0.00, 0.05, 0.10, 0.20, and 0.30 were prepared. Phase identification, structural and microstructural analysis were carried out using powder X-ray diffraction method, scanning electron microscopy and energy dispersive X-ray (EDX) analysis. The transition temperature and the critical current measurements were carried out using the electromagnetic measurement system. The critical parameters of the samples were also determined by AC susceptibility and magnetization measurements. Improvements in the formation of the Bi-2223 phase with Nb addition have been observed by both methods. The ANM method leads mixtures of Bi-2223 and Bi-2212 phases, but with the SSR method pure Bi-2223 phase was obtained. With small amounts of Nb addition the critical temperature, Tc, remains the same for ANM samples and it increases for the SSR samples. For both series of samples Tc decreases with further increase of Nb content. With Nb addition the critical currents of the ANM sample almost remain the same and those of the SSR samples increases. Observations based on AC susceptibility measurements showed that Nb addition improve inter-grain coupling. Inductive critical current densities obtained from magnetization measurements agree with the critical currents stated above and show that Jc increase with increase Nb content.


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Cavdar, S; Aksu, E; Koralay, H; Ozkan, H; Hasanlı, Nızamı; Ercan, I (Wiley, 2003-09-01)
We have studied the effect of B2O3 addition on the formation and properties of the Tl-based superconductors. Polycrystalline Tl-2212 and Tl-2223 samples were synthesized by adding B2O3 to the chemicals at the first and at the second stage of two stages sintering processes (3+1 h) at 860 C. X-ray powder diffraction patterns, resistance versus temperature behaviours and the micrographs of the B2O3 free and B2O3 added samples have been analysed. The compositions and the critical temperatures of the samples ind...
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Ogun, SE; Ozkan, H; Hasanlı, Nızamı (Institute of Electrical and Electronics Engineers (IEEE), 2003-06-01)
The effect of Li addition on the formation and properties of Pb containing Bi-based superconductors has been studied. Three successive thermal sintering cycles have been applied to the oxides adjusted for the nominal composition, Bi1.6Pb0.4Sr2CaCu2O8+d. Eight different samples having Li2CO3 from 0.0 up to 3.0 weight% have been synthesized, X-ray diffraction patterns, resistivity-temperature behaviors and differential thermal analysis of the samples have been examined. Li2CO3 addition at 650degreesC decrease...
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Kayed, TS; Ozkan, H; Hasanlı, Nızamı (IOP Publishing, 2001-09-01)
The effects of lithium doping on the formation and properties of the T1-based superconductors have been studied. Lithium atoms up to around 3 mol.% have been added to the oxides of nominal composition Tl1.8Ba2Ca2.2Cu3Ox, and the usual solid-state reaction method has been applied. Lithium additions in the range 0.23-0.29 mol.% increase the fraction of the Tl-2223 phase and significantly improve the critical temperature of the samples. Higher amounts of lithium additions diminish the Tl-2223 phase, reduce the...
Effect of Microstructure on the Mechanical Behavior of Reactive Magnetron Sputtered Al2O3/TiO2 Multilayer Ceramics
Dericioğlu, Arcan Fehmi (Japan Institute of Metals, 2008-11-01)
Mechanical characteristics of reactive magnetron sputtered Al2O3-TiO2 multilayer ceramics were studied. Tailored mechanical properties such as moderately high hardness and reasonable toughness were achieved through varying sputtering process parameters resulting in microstructural control at nano-scale. Interchanging Al2O3 and TiO2 layers with a single layer thickness of similar to 65-70 nm were deposited on single crystal alumina (sapphire) substrates to form the multilayer structure composed of 10 layers....
Effect of Presoaked Expanded Perlite Aggregate on the Dimensional Stability and Mechanical Properties of Engineered Cementitious Composites
KESKİN, SÜLEYMAN BAHADIR; Sulaiman, Kamaran; Sahmaran, Mustafa; Yaman, İsmail Özgür (American Society of Civil Engineers (ASCE), 2013-06-01)
This paper reports on an investigation of the use of expanded perlite aggregate as saturated lightweight aggregate (LWA) with respect to the mechanical and dimensional stability properties of engineered cemetitious composites (ECC). Expanded perlite aggregate was soaked in water for 24 h before its use in ECC, and replaced 10, 20, and 30% of the aggregate that was used in ECC production. The mixture proportion of a standard ECC mixture with properties that have been extensively reported in the literature is...
Citation Formats
N. Ghazanfari, “Effects of Nb2O5 addition on the formation and properties of Bi-based superconductors,” M.S. - Master of Science, Middle East Technical University, 2006.