Synthesis and Characterization of Superconducting Nanofibers

Ceramics International, 2017

This paper presents the synthesis and characterization of BSCCO superconducting fibers synthesized by heattreating poly(vinyl pyrrolidone) (PVP)/BSCCO precursor microfibers produced by the solution blow-spinning technique. Different concentrations (v/v) of the BSCCO precursor were added to the PVP solution to evaluate the influence of solution viscosity on fiber morphology. The production of PVP/BSCCO microfibers and their morphology were strongly influenced by the volatility of the solvent and the concentration of the added BSCCO in the solution. After heat-treatment, fibrous structures were obtained for the BSCCO system. The structural properties of the samples were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The XRD pattern revealed the formation of Bi 2 Sr 2 Ca 1 Cu 2 O x and Bi 1,9 Sr 1,8 CuO 5,5 phases. Finally, electrical measurements (R×T) showed electrical resistance decay at the transition temperature (Tc) that was typical of that observed in superconductor materials.

Physica C: Superconductivity, 2013

This paper presents the synthesis and characterization of Bi 2 Sr 2 CaCu 2 O 8+x superconducting nanowires. Bi 2 Sr 2 CaCu 2 O 8+x nanowires with a T c = 78.7 K are synthesized using the electrospinning process employing sol-gel precursors. A sol-gel methodology is used to obtain a homogeneous PVP solution containing Bi, Sr, Ca, and Cu acetates. Mats of randomly oriented nanowires and aligned nanowires are also collected. After a heat treatment at 850°C in ambient atmosphere using heating rates of 100 and 400°C/h, fully crystallized Bi 2 Sr 2 CaCu 2 O 8+x nanowires are obtained. The morphology, microstructure, and crystal structure of these nanowires are then examined to reveal a rectangular morphology having typical wire thickness in the range of 150-250 nm, and a wire width between 400 and 600 nm. DC magnetization studies are conducted to investigate the critical transition temperature (T c) of Bi 2 Sr 2 CaCu 2 O 8+x nanowires and to compare their magnetic properties to those of bulk Bi 2 Sr 2 CaCu 2 O 8+x powder. The T c for the commercial powder is observed at 78.6 K, and that of the obtained nanowires at 78.7 K. These results point to the superconducting nature of Bi 2 Sr 2 CaCu 2 O 8+x nanowires, and the potential of the electrospinning process for the synthesis of this superconductor material.

Al-Nahrain journal of science, 2022

The high-temperature superconductor like YBa2Cu3O6.5+ was prepared by solid-state reaction method at calcination temperatures (900 °C). The crystal structure was confirmed using X-ray diffraction, and it was found that YBa2Cu3O6.5+ showed orthorhombic phase with lattice parameters (a = 3.82030, b = 3.88548, and c = 11.6835 Å) with space group (Pmmm). The sample was sintered at sintering temperatures (900 °C) for (24 hr). The oxygen excess () was nearly (0.36), which was effective in the appearing superconducting properties. The sample YBa2Cu3O6.86 had a critical temperature of about (92 K). The simulation on the XRD-pattern was necessary to predicate the shape of the unit cell and the position of atoms in the unit cell. The last is very important to find some theoretical date, which are benefit in the predication the conductivity parameters through the sequence's unit cells, which are useful in the conductivity mechanism. This mechanism is depending on the concept of interlayer coupling, so the number of the layers including the unit cell is effective parameter in the conductivity mechanism through the normal resistivity created.

Journal of The American Ceramic Society, 2009

The preparation of large-scale YBa2Cu3O7−x superconductor samples was investigated. This method is based on plastic forming using a slurry consisting of YBa2Cu3O7−x particles and a sol solution made up of multimetallic hydroxide particles (YBa2Cu3(OH)x colloidal particles) and poly(vinyl) alcohol (PVA). The effects of adding PVA on the product, the crystallinity, and the superconducting properties of the sample were investigated. It was found that PVA acted as a protective colloid in the sol solution and stabilized YBa2Cu3(OH)x colloidal particles, and that the role of PVA changed from a thickener to a flocculant during drying so that the formability/workability of the green sheet sample was improved and large samples (about 80 mm × 80 mm × 3 mm) without large cracks were obtained after firing. The samples became superconducting at 91.5±0.5 K (Tcon) and the full transition temperature (Tcoff) was 88.5±1.5 K. The critical current density (Jc) of the sample prepared from the slurry containing 1 wt% PVA was 713±150 A/cm2 at 77 K. This Jc value was improved to 2300 A/cm2 by heat treatment at 773 K under an oxygen atmosphere.

Ceramics International, 2019

The effect of YBa 2 Cu 3 O 7-δ (YBCO) inoculated with a small amount of magnetoelectric YMnO 3 (YMO) is presented. The particulate composites YBCO-x%YMO (x = 0.10, 0.25, 0.50, 0.75, 1.00 and 5.00 wt%) were investigated for microstructural and physicochemical properties. The YBCO precursor exhibits two characteristic peaks of crystallite sizes around 50 µm and 300 µm after the second calcining process. The vibrational spectra shows a small deterioration of the superconducting state of YBCO-YMO ceramics across the YMO content, which is due to the vanishing of the orthorhombic phase seen as a O(4) band moves towards the higher wave numbers on the Raman scale. From the magnetic measurements one can find that a small addition of YMO (around 1.00 wt%) does not significantly change the superconducting properties of YBCO crystallites, and most of the composites exhibit critical temperature T c close to 92 K. The direct magneto-resistance measurements at 77 K show critical current densities (J c ) of 205 A•cm -2 for YBCO-0.25%YMO and 35 A•cm -2 for YBCO-5.00%YMO, respectively.

International Journal of Inorganic Materials, 2001

The role of Ag-additions in the synthesis of bulk YBa Cu O is extremely varied. In order to separate and understand some aspects of 2 3 7 these introductions, this paper describes the synthesis of two series of bulk samples with different thermal histories as a function of their silver content up to very high loadings (0-80 wt.%), which may have industrial significance. Their morphological and thermal characteristics are discussed and their superconducting properties are studied in detail using AC and DC susceptometry at high and low field. They exemplify the role of silver as flux at high temperatures and as mediator of oxygen transport at lower temperatures.

Journal of the European Ceramic Society, 1997

Bulk YBa,Cu,O,-Y,BaCuO, textured ceramic composites of dtflerent shapes and sizes have been prepared through a directional solidtfication process. Green ceramic preforms for the directional solid@cation process have been obtained by using uniaxial pressures for the fabrication of pellets, ceramic moulds at low pressures for bars, cylinders and rings, and wet extrusion for the fabrication of jibres. We have studied dtfberent ratios of both phases, particle sizes, CeO2 additions and temperature dependence. The directional solidt$cation process allows to obtain quasi-single crystal superconductors with critical currents above IO' A/cm2 at 77 K and 0 1996 Elsevier Science Limited. zero field.

Materials Research Bulletin, 1988

YBa2Cu307. X superconducting materials have been obtained from oxalate coprecipitation and metalloorganic decomposition. Resistivity and magnetic measurements confirm the superconducting behavior below 90 K. Calorimetric measurements reveal the role of impurities in the specific heat evolution.

Materials Today: Proceedings, 2016

New route synthesis of YBCO / graphene composite material is described in the present work. The oxide mixture and graphene were obtained separately and then mixed together by ball milling in the mass ratio graphene: YBCO = 1: 100. The oxide mixture was prepared by modified auto combustion reaction starting from stoichiometric amounts of yttrium acetate and barium and copper nitrates without any other organic compound addition. Graphene materials were prepared by reducing GO (i.e. oxidation of graphite powder by a modified Hummers method) with hidrazine sulphate. The final material resulted by applying the ballmilling method was investigated by XRD, SEM, Raman and HRTEM.

Chemistry of Materials, 2003

Copper nanowires with multiwall carbon nanotubes (MWNTs) encapsulated inside were prepared via surface modification of MWNTs followed by chemical deposition of copper on surfaces. These MWNTs-encapsulated copper nanowires were investigated as a reinforcement to improve the mechanical strength of the Y-Ba-Cu-O superconductor. TEM and SEM reveal that MWNTs are uniformly coated by copper and the diameters of the prepared MWNTs-encapsulated Cu nanowires range from 50 to 150 nm and the lengths are up to several micrometers. These MWNTs-containing Cu nanowires could effectively improve the hardness of the Y-Ba-Cu-O without sacrificing its superconductivity. The Vicker's hardness of the Y-Ba-Cu-O is reinforced by ∼20% after 5 wt % of MWNTs incorporation. This study presents the first result that demonstrates the feasibility of the reinforcement of brittle YBaCuO superconductor by using MWNTs.