Synthesis, microstructural evolution and the role of substantial addition of PbO during the final processing of (Bi,Pb)-2223 superconductors

Azzouz, F. Ben; M’chirgui, A.; Yangui, B.; Boulesteix, C.; Salem, M. Ben

doi:10.1016/s0921-4534(01)00124-1

Cited by 60 publications

(24 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Part of the obtained pellet was cut into a bar with dimensions 5x2x1 mm 3 for resistivity measurements, part was used for energy-dispersive X-ray analysis (EDAX) and electron microscopy and part was ground again for powder X-ray diffraction. Details of preparation and these investigations have been published previously [6]. All of these measurements indicate that both Bi-2212 and (Bi,Pb)-2223 samples are almost single-phase.…”

Section: Methodsmentioning

confidence: 88%

Fluctuation conductivity analysis on the Bi‐based superconductors processed under same conditions

Azzouz

Zouaoui

Annabi

et al. 2006

Phys. Status Solidi (c)

Self Cite

View full text Add to dashboard Cite

We report electrical conductivity fluctuation measurements on different Bismuth-based granular samples synthesized under same processing conditions.Using the fluctuation conductivity ∆σ as a function of the reduced temperature ε in the range -7 < lnε < 1, we identified Gaussian and critical fluctuation conductivity in (Bi,Pb)-2223 and Bi-2212 samples. Within the mean field region, samples show predominately two dimensional (2D) behaviour with exponent λ = − 1. Closer to critical temperature T C , we have observed a crossover of λ from -2/3 to -1/3 in the critical region. The obtained exponents are consistent with 3D-XY model predictions. The regime with the critical exponent -2/3 is dominate in the case of (Bi,Pb)-2223 sample.1 Introduction The salient features of high-temperature superconductors (HTSC), besides their pronounced granular character, are the short superconducting coherence lengths and the quasi 2D electronic conduction. These distinctive characteristics enhance thermodynamic fluctuation effects, produce a significant rounding of the transition curve and thus greatly enlarge the temperature region in which fluctuations of the order parameter ψ are important. Thermodynamic fluctuations arise due to the Copper pair breaking phenomenon that may be caused by higher disorder media or higher amount of impurities. A detailed and systematic analysis of these fluctuations can provide important information regarding intrinsic properties and dimensionality of superconducting systems especially in the vicinity of the critical temperature T C . which was determined by the derivative temperature resistivity dρ⁄dT. When the temperature approaches close enough to T C and exceeds the Ginsburg temperature T G at which the fluctuations in the amplitude of the order parameter become of the same order as itself, the mean-field theory with Gaussian corrections is not expected to be valid. This yields a temperature interval c

show abstract

Section: Methodsmentioning

confidence: 88%

Fluctuation conductivity analysis on the Bi‐based superconductors processed under same conditions

Azzouz

Zouaoui

Annabi

et al. 2006

Phys. Status Solidi (c)

Self Cite

View full text Add to dashboard Cite

show abstract

“…According to the table, the H 0 , E 0 and Y 0 values decrease with the increment in the Lu inclusions in the Y123 matrix. The Vickers microhardness values of the pure material exhibiting the RISE behavior are found to greater than those of the Lu-doped samples presenting the ISE feature due to the lack of the elastic recovery [34][35][36]. In other words, the plastic as well as the elastic deformation is produced in the materials obeying the ISE behavior.…”

Section: Analysis According To Psr Modelmentioning

confidence: 88%

Experimental and theoretical approaches on mechanical evaluation of Y123 system by Lu addition

Turkoz

Nezir

Öztürk

et al. 2013

J Mater Sci: Mater Electron

View full text Add to dashboard Cite

This work is the continuation of a systematic study on the characterization of the Lu-added Y123 bulk superconducting materials prepared by the nitrate compounds and derivatives at 970°C for 20 h. In this part, the effect of Lu inclusions on the physical and mechanical properties of the Y123 superconductors is examined with the aid of microhardness measurements performed at various applied loads in the range of 0.245-2.940 N. The microhardness measurement results allow us to determine the important mechanical characteristics such as Vickers microhardness, elastic (Young's) modulus, yield strength and fracture toughness values being responsible for the potential industrial applications. It is found that all the properties given above are strongly dependent upon the Lu concentration in the Y123 matrix. Especially, Vickers microhardness (H v ) values of the samples studied in this work are found to suppressed considerably with the enhancement of the Lu addition in the system due to the degradation in the connectivity between superconducting grains. Moreover, the H v values of the pure Y123 sample are observed to increase with increasing the applied load whereas those of the Lu-doped superconducting materials are obtained to decrease with the load. In other words, the pure sample exhibits the reverse indentation size effect (RISE) behavior while the others obey the indentation size effect (ISE) feature, confirming the degradation in the mechanical properties with the Lu inclusions in the Y123 matrix. In addition, the microhardness measurement results are estimated using the 5 different models such as Meyer's law, proportional sample resistance model, elastic/plastic deformation model, Hays-Kendall (HK) approach and indentation-induced cracking (IIC) model. According to the results obtained from the simulations, of the mechanical analysis models, the Hays-Kendall (HK) approach is determined as the most successful model for the description of the mechanical properties of the Lu-doped superconducting materials (exhibiting the ISE behavior) where both the both the reversible (elastic) and irreversible (plastic) deformations are produced. On the other hand, the IIC model is found to be superior to other approaches for the pure sample (presenting the RISE feature) where the irreversible deformation becomes more and more dominant compared to the reversible deformation.

show abstract

“…Superconducting Bi 2 Pb 1 Sr 2 Ca 2.2 Cu 3.2 O y material for the target is prepared by the standard solid-state reaction method [39,40] using high purity oxides and carbonates (Alfa Aesar Co., Ltd. 99.99% purity). The accurately weighted ingredients are grounded homogeneously with the aid of a grinding machine for 24 h with a rotation speed of 2000 rpm in 10 min in a medium of atmospheric air and calcined in a tube furnace (Protherm-Model PTF12/75/200) at 800°C for 12 h with a heating rate of 5°C/min.…”

Section: Methodsmentioning

confidence: 99%

Effect of Annealing Time and Temperature on Microstructural and Superconducting Properties of (Bi,Pb)-2212 Thin Films Produced by Magnetron Reactive Sputtering

Bal

Varılcı

2012

J Supercond Nov Magn

View full text Add to dashboard Cite

This study deals with the role of various annealing time (1 h, 2 h, 4 h, 6 h and 8 h) and temperature (840 and 850°C) on the microstructural and superconducting properties of thin films with the aid of scanning electron microscopy (SEM), X-Ray analysis (XRD), electron dispersive X-Ray (EDX), resistivity and transport critical current density (J c ) measurements. The T c , J c , variation of transition temperatures, hole-carrier concentration, grain size, phase purity, lattice parameter, surface morphology, element distribution, crystallinity and resistivity (at room temperature) values of the films prepared are compared with each other. Critical transition temperatures (T c ) of the samples are deduced from the dc resistivity measurement while critical current density values are estimated from the critical current and total cross-sectional area values. It is found that maximum T c of 79.7 K and J c of 1520 A/cm 2 are observed for the film annealed at 840°C for 6 h as against 54.9 K and 30 A/cm 2 (minimum values), respectively, for the film annealed at 840°C for 4 h. Moreover, SEM images indicate that the former has the best crystallinity, grain connectivity and largest grain size. Based on these results, T c and J c values of the samples studied are found to depend strongly on the microstructure. Additionally, EDX results show that the elements used for the preparation of all the samples are observed to distribute homogeneously. As for the XRD results, all the samples exhibit the polycrystalline superconducting phase with the changing intensity This study is devoted to Gulnur Ozdemir on the occasion of her 26th Birthday. of diffraction lines. According to the refinement of cell parameters done by considering the structural modulation, the largest lattice parameter a and c are obtained for the film annealed at 840°C for 8 h. To sum up, the aim of the present study is not only to investigate the changes of microstructural and superconducting properties of the samples fabricated in the varied time and temperature but to determine the best ambient for the film fabrication and show the feasibility of obtaining Bi-2212 film with tailored structure, as well.

show abstract

Synthesis, microstructural evolution and the role of substantial addition of PbO during the final processing of (Bi,Pb)-2223 superconductors

Cited by 60 publications

References 29 publications

Fluctuation conductivity analysis on the Bi‐based superconductors processed under same conditions

Fluctuation conductivity analysis on the Bi‐based superconductors processed under same conditions

Experimental and theoretical approaches on mechanical evaluation of Y123 system by Lu addition

Effect of Annealing Time and Temperature on Microstructural and Superconducting Properties of (Bi,Pb)-2212 Thin Films Produced by Magnetron Reactive Sputtering

Contact Info

Product

Resources

About