Volume Fraction Of Bi-2223 Phase Research Articles

Study the effects of MgO nanoparticle addition on superconducting characteristics of Bi1.6 Ag0.4Sr1.9Ba0.1Ca2Cu3O10+δ system

In the present work, impacts adding magnesium oxide (MgO) powders with a mean particle size <100nm to Bi2223 superconducting system have been researched. The bulk samples with a general Bi1.6 Ag0.4Sr1.9Ba0.1Ca2Cu3O10+δ + (MgO)x nominal composition formula (x = 0, 0.1, 0.2, and 0.3wt%) have been made through the traditional solid state reaction approach. Hole concentration (p) and Critical temperature (Tc) of the nano MgO added samples have been specified through 4 probe techniques. X-ray powder diffraction (XRD) measurement has been utilized for examining the formation of the phase, lattice parameters and volume fraction. The results of the XRD had shown that lattice parameters are changed with the increase of the addition of the nano Mg. It has been observed as well from the measurements of the XRD that volume fraction of Bi2223 phase is increased with the increase in the addition of the nano Mg. Bi2223 phase volume fraction for non-added sample had shown that the maximum value as 77% and additionally increasing the nano MgO, Bi2223 phase’s volume fraction is increased with the increase in the Bi2212 phase. The sample with addition of 0.3wt% MgO had shown the maximum Bi2223 phase volume fraction (about 80%) and maximum super-conducting transition temperature, Tc (up to 141K) in comparison with added samples with the nano MgO.

Investigation of effects of MgO nanoparticles addition on the superconducting properties of Bi-2223 superconductors

In this study, the effects of addition of magnesium oxide powders with average particle size <100 nm to Bi-2223 superconducting system were investigated. Bulk samples with general formula of Bi1.7Pb0.3Sr2Ca2Cu3Oy + (MgO)x nominal composition (x = 0.00, 0.05, 0.10, 0.15 and 0.20 wt%) were prepared by conventional solid state reaction method. The critical temperature (Tc) and hole concentration (p) of nano MgO added samples were determined by AC susceptibility measurements. X-ray powder diffraction measurement (XRD) was used to examine phase formation, volume fraction and lattice parameters. The microstructure and surface morphology analyses of the samples were determined by scanning electron microscope. As Nano Mg addition was increased, surface morphology and grain connectivity of the samples were observed to degrade. XRD results showed that the lattice parameters do not change with increasing nano Mg addition. It was also observed from XRD measurements that volume fraction of Bi-2223 phase decreases with increasing nano Mg addition. The volume fraction of Bi-2223 phase for the non-added sample showed the highest value as 62.7% and further increasing nano MgO, the volume fraction of Bi-2223 phase decreases while Bi-2212 phase increases. The sample with 0.20 wt% MgO addition showed the highest volume fraction of Bi-2223 phase (~56%) and the highest superconducting transition temperature, Tc (~106 K) compared to added samples with nano MgO. The effect of nano Mg addition on magnetic properties of Bi1.7Pb0.3Sr2Ca2Cu3Oy superconductors were investigated by AC susceptibility measurements performed at ac fields of 1 Oe with f = 1000 Hz. The results revealed that critical temperature (Tc) decreases with increasing nano Mg addition down to 99.16 K.

The influence of Ag substitution on structural and mechanical properties of (Bi, Pb)-2223 ceramics

In this work, Bi1.7Pb0.3Sr2Ca2Cu3−xAgxOy (x = 0.00, 0.03, 0.06, 0.09, 0.12) ceramics were prepared by conventional solid state reaction method. The effects of Ag substitution on the structural and mechanical properties of the samples were investigated by Vickers microhardness, X-ray powder diffraction (XRD) measurements and scanning electron microscope (SEM) analysis. The phase formation, volume fraction and lattice parameters were characterized by using XRD measurements. Surface morphology and grain connectivity of the samples were identified by using SEM. The mechanical properties were analyzed by microhardness measurements. Load dependent microhardness, elastic modulus, yield strength and fracture toughness were obtained by hardness measurements. XRD results indicated that the lattice parameter c decreases with increasing Ag addition. It was also observed that volume fraction of Bi-2223 phase decreases with increasing Ag addition from XRD measurements. SEM results showed that the surface morphology and grain connectivity improve, the grain sizes and porosity of the samples decrease with increasing Ag addition. Vickers microhardness (Hv), Young’s modulus (E), yield strength (Y) and fracture toughness (KIC) values were calculated separately for all samples. In our study, Young’s modulus, yield strength, and fracture toughness of the samples indicated dependency on applied load. It was seen that the load dependent Hv, E, Y, and KIC increase with increasing Ag and decreasing applied load. Experimental results of the microhardness measurements were analyzed using two models such as elastic–plastic deformation model and the energy dissipative model. Energy dissipative model was determined as the most successful model describing the mechanical properties of our samples.

Enhancing Phase Purity of CSD Bi-2223 Thin Films Through Protected Sintering Method

Pure Bi 2 Sr 2 Ca 2 Cu 3 O x (Bi-2223) phase is hard to be achieved in Bi-2223 thin films fabricated by using chemical solution deposition (CSD) due to the volatilization of specific elements. Two protected sintering methods were proposed in this work to enhance the phase purity of CSD Bi-2223 thin films. One method is two deposited thin films stacked “face-to-face” (FTF) and then sintered. A “substrate/precursor film/precursor film/substrate” architecture was used during sintering instead of common “precursor film/substrate” architecture. The other method was named “sealed face-to-face” (SFTF). The FTF structure was buried in Bi-2223 powders and then sealed in a silver envelope before sintering. Different sintering temperature and sintering time were investigated in an 8% O 2 (N 2 balance) atmosphere. The volume fraction of Bi-2223 phase could be enhanced to 17% by using the FTF method, and 68% by using the SFTF method.

Effect of Nb addition on magnetic, structural and superconducting properties of (Bi, Pb)-2223 superconductors

In this work, the effects of Nb2O5 addition with different ratios on the structural and magnetic properties of Bi1.7−xPb0.3NbxSr2Ca2Cu3Oy (x = 0.00–0.20) superconducting samples were investigated. (Bi, Pb)-2223 superconducting samples were prepared by conventional solid-state reaction method. The phase formation, phase fraction and lattice parameters were determined from X-ray powder diffraction (XRD) measurements, the microstructure, surface morphology analyses of the samples were carried out using scanning electron microscope (SEM). Additionally, ac susceptibility measurements were done in order to determine the critical current density (Jc) and hole concentration (p) of the samples. AC susceptibility measurements were done at various ac fields (ranging from 20 to 160 A/m) to understand the effect of Nb addition on magnetic properties of Bi1.7−xPb0.3NbxSr2Ca2Cu3Oy superconductor. Critical onset (T c on ) and loss peak temperatures (Tp) were estimated from the ac susceptibility curves. It was observed from ac susceptibility measurements that the critical onset temperatures decreased from about 108–98 K with increasing Nb addition (x = 0.00–0.20). The imaginary part of susceptibility was used to calculate the intergranular critical current density (Jc) by means of the Bean’s model. X-ray diffraction analysis revealed that the samples consisted of a mixture of Bi-2223 and Bi-2212 phases as the major constituents and non-superconducting phase Ca2PbO4 as the minor. It was also shown from XRD measurements that volume fraction of high-Tc phase decreases with increasing Nb addition up to x = 0.20. The sample with Nb addition of x = 0.20 showed the highest volume fraction of Bi-2223 phase (86 %). When Nb addition was increased, the surface morphology and grain connectivity are found to degrade, the grain sizes decrease and porosity of the samples were observed to increase from SEM images except the sample with x = 0.20 Nb addition.

Effects of heating rate on the phase and microstructure evolution in Bi-2223/Ag/Ni superconducting tapes

Effects of heating rate on the phase and microstructure evolution in Bi-2223/Ag/Ni superconducting tapes were studied. It was found that 30°C/h, the lowest heating rate, was the most suitable to obtain microstructure improved tapes. The volume fraction of Bi-2223 phase increased and the amount and size of secondary phases decreased with the heating rate reducing. Meanwhile, the optimal texture formed earliest in the samples heated at 30°C/h. The size of Bi-2212 grains is the largest in the samples heated at 30°C/h, which may lead to the largest size of Bi-2223 grains eventually.

Effect of Yb Substitution in Bi&lt;sub&gt;1.6&lt;/sub&gt;Pb&lt;sub&gt;0.4&lt;/sub&gt;Sr&lt;sub&gt;2&lt;/sub&gt;Ca&lt;sub&gt;2-&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt;Yb&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt;Cu&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;&lt;i&gt;y&lt;/i&gt;&lt;/sub&gt; Superconductor

This paper reports on the results of Yb substitution for Ca on the superconductivity and structural properties of Bi1.6Pb0.4Sr2Ca2-xYbxCu3Oy superconducting samples with x = 0.000, 0.025, 0.050, 0.100 and 0.200 which prepared by coprecipitation (COP) method. The samples were characterized by X-ray diffraction (XRD), field-emission scanning electron (FESEM), electrical and resistivity measurement by four-probe method. It was found that the substitution of Yb decreased the critical temperature (Tc zero), critical current density (Jc) and volume fraction of Bi-2223 phase. The samples have Tc zero in the range 77 to 100 K. Tc zero gradually decreased with an increase in Yb concentration, corresponding to small change of the carrier concentration. Jc was measured to be 5.7512 A/cm2 for pure sample and decreased to 4.1910 A/cm2 for x = 0.025 at 77 K. The crystallographic structure was found to change slightly from tetragonal to orthorhombic in Yb substituted samples. The lattice parameter c of Yb samples decreased due to the incorporation of Yb3+ (0.858 Å) with smaller ionic size compare to Ca2+ (0.99 Å). From the SEM observation, the grain connectivity became weak with smaller plate-like grain for x &gt; 0.025 Yb concentration resulting in the decreased of Jc.

The effect of MgCO 3 addition on the superconducting properties of Bi2223 superconductors

MgCO 3 particles were introduced into Bi 1.66Pb .34Sr 2Ca 2Cu 3O 10+ δ powder in various weight fractions. Bulk samples were made from the Bi2223/MgCO 3 powder by the conventional solid state reaction method. The superconducting properties of samples for different amounts of MgCO 3 have been investigated by means of X-ray diffraction, magnetoresistivity. Room temperature X-ray diffraction studies show that there exists two phases, i.e. Bi2223 and Bi2212 in analyzed samples. The volume fraction of Bi2223 phase decreases with increasing MgCO 3 content. It is observed that the lattice parameter c decreases with increasing MgCO 3 content, but a (and/or b) axis does not change considerably. The temperature at which the resistivity becomes zero decreases with increasing dopant content and also with increasing applied magnetic field. The normal state resistivity regularly decreases with the increase in MgCO 3 addition.