Synthesis and Superconducting Properties of Metastable Y(Ba2−xYx)Cu3O7+δ

ABSTRACTThe oxygen-deficient orthorhombic oxide YBa2Cu3O7-δ has been the center of intense recent interest because of its high Tc superconducting proper-ties[l-3]. Recently, the structurally related La3Ba3Cu3O15-δ, has received increasing attention[4–9]. The pure Y analog[10,11] cannot be synthesized by usual solid state reaction routes probably because of its metastability near 880°C. Here we report on the successful synthesis of pure tetragonal Y3,Ba3CU6O15-δ (referred to as Y 3–3–6), via the firing of an atomically mixed citrate precursor at a relatively low temperature. X-ray diffraction data characterize Y 3–3–6 to be isostructural with the corresponding La compound[4]. The unit cell composition can then be written as: Y(Ba2−x Yx) CU3O7+δ with the parent compound at x = 0.50. Specimens of Y 3–3–6 at × = 0.50 and 0.375 annealed at 650°C under 1 atmosphere of O2 are non-superconducting. Higher pressure O2 annealing and fluorine-doping leads to a 1–5% superconducting volume fraction with onset at 85K. Annealing near 880°C creates a 10% superconducting fraction which shows near-zero resistivity at 62K and a reproducible, small resistive transition near 260K.

Download Full-text

Effect of the BSCCO superconducting properties by tiny Y2O3 addition

Modern Physics Letters B ◽

10.1142/s0217984916503280 ◽

2016 ◽

Vol 30 (26) ◽

pp. 1650328

Author(s):

Yan Dong ◽

Aimin Sun ◽

Bin Xu ◽

Hongtao Zhang ◽

Meng Zhang

Keyword(s):

Volume Fraction ◽

Superconducting Properties ◽

X Ray Diffraction ◽

Critical Transition Temperature ◽

Solid State Reaction Technique ◽

X Ray ◽

Oxide Addition ◽

One Step ◽

Step Transition ◽

Y2o3 Addition

In this paper, the effect of tiny Y2O3 addition in (Bi,[Formula: see text]Pb)-2223 superconductor prepared by solid state reaction technique was studied. The properties of samples have been investigated via X-ray diffraction (XRD), resistance–temperature ([Formula: see text]–[Formula: see text]) curve, scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). XRD data indicated that all samples are multiphase and the major phases are high-temperature phases and low-temperature phases. The volume fraction of (Bi,[Formula: see text]Pb)-2223 is not great change with tiny Y2O3 addition. All samples exhibit superconducting phase with the critical transition temperature and one-step transition, however, the transition width was decreased with the Y2O3 addition up to 0.04 wt.% and sharp increased with the excessive oxide addition. SEM pictures show that the Y2O3 appeared on the flake-type grains surface obviously, but the number and size of the hole between grains are decreased in the 0.04 wt.% addition.

Download Full-text

TIN ADDITION TO THE (Bi, Pb) 2223 SYSTEM

Modern Physics Letters B ◽

10.1142/s0217984994001163 ◽

1994 ◽

Vol 08 (19) ◽

pp. 1175-1183 ◽

Cited By ~ 1

Author(s):

G. RAVI CHANDRA ◽

B. GOPALA KRISHNA ◽

S. V. SURYANARAYANA ◽

T. S. N. MURTHY

Keyword(s):

Heat Treatment ◽

Magnetic Susceptibility ◽

Electrical Resistance ◽

Volume Fraction ◽

Ac Magnetic Susceptibility ◽

Superconducting Properties ◽

X Ray Diffraction ◽

Metallic Behavior ◽

X Ray

The effect of the addition of Sn on the superconducting properties of the Bi 1.7 Pb 0.3 Sr 2 Ca 2 Cu 3 O y system as functions of Sn concentration and heat treatment has been studied by dc electrical resistance, ac magnetic susceptibility, and X-ray diffraction. Tin addition suppresses the volume fraction of the high T c phase. Samples with Sn > 0.1 show metallic behavior up to LNT. The formation of the Ca 2 PbO 4 phase is promoted by Sn. This depletes the amount of Pb and Ca necessary for the formation of the 2223 phase, thus reducing the volume fraction of the 2223 phase. It is possible that at least a small fraction of tin substitutes some of the cationic sites of the starting composition. The results of the different measurements are presented.

Download Full-text

High Density Bulk Shape Rapid Consolidation of the Yba2Cu307-X Superconductor

MRS Proceedings ◽

10.1557/proc-169-1223 ◽

1989 ◽

Vol 169 ◽

Cited By ~ 1

Author(s):

S. V. Rele ◽

R. V. Raman ◽

H. S. Meeks ◽

R. L. Anderson ◽

R. N. Shelton ◽

...

Keyword(s):

Volume Fraction ◽

X Ray Diffraction ◽

X Ray ◽

Superconducting Volume Fraction ◽

One Step ◽

Hollow Cylinders ◽

Diffraction Patterns ◽

Set Up ◽

Cylinders And Spheres ◽

High Processing

AbstractA novel rapid densification technique for fabrication of bulk shape YBa2Cu307–xsuperconductor is presented. The Ceracon process is a one‐step, quasi‐isostatic consolidation route utilizing conventional P/M equipment and set‐up. The Ceracon technology has enabled successful fabrication of bulk, shapes such as discs, cylinders, hollow cylinders and spheres along with significant increases in the density up to 95‐98% of the theorertical. The superconducting volume fraction is preserved due to short hold times at the operating temperatures and avoidance of high processing temperatures. Results based on densities, microstructure, susceptibility measurements, X‐ray diffraction patterns and TGA measurements are discussed.

Download Full-text

Superconducting Properties of Bi-Sr-Ca-Cu-O Crystallized Glass

International Journal of Modern Physics B ◽

10.1142/s0217979299000837 ◽

1999 ◽

Vol 13 (09n10) ◽

pp. 985-989

Author(s):

S. Chudinov ◽

S. Stizza ◽

B. Kościelska ◽

L. Murawski ◽

W. Sadowski ◽

...

Keyword(s):

Magnetic Field ◽

Glass Ceramics ◽

Superconducting Phase ◽

Superconducting Transition ◽

Resistive Transition ◽

Superconducting Properties ◽

X Ray Diffraction ◽

Melt Quenching ◽

X Ray ◽

Quenching Method

This paper reports the crystallization and superconducting properties of Bi 4 Sr 3 Ca 3 Cu 4 O x glass-ceramics. The glass was prepared using the conventional melt-quenching method. X-ray diffraction pattern has shown that the annealing at temperature of 800°C converted the glass into glass-ceramics with Bi 2 Sr 2 CaCu 2 O x superconducting phase (2212-phase). The superconducing transition exhibits the change in the slope that is characteristic for two different superconducting phases. It is observed that T c (zero) increases from 20 K to 80 K with increasing time of annealing. The influence of magnetic field on the superconducting transition has been investigated. Our studies revealed a remarkable broadening of the resistive transition as a function of temperature with increasing field. The temperature width ( T c-T) of the transition for both phases increases with magnetic field according to Tinkham model.

Download Full-text

Role of the extra Fe in K2−xFe4+ySe5 superconductors

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1815237116 ◽

2019 ◽

Vol 116 (4) ◽

pp. 1104-1109 ◽

Cited By ~ 3

Author(s):

Chih-Han Wang ◽

Chih-Chien Lee ◽

Gwo-Tzong Huang ◽

Jie-Yu Yang ◽

Ming-Jye Wang ◽

...

Keyword(s):

Volume Fraction ◽

Parent Compound ◽

Superconducting Transition ◽

X Ray Diffraction ◽

X Ray ◽

Heat Treated ◽

Different Temperatures ◽

Two Phases ◽

Best Fit

The exact superconducting phase of K2−xFe4+ySe5 has so far not been conclusively decided since its discovery due to its intrinsic multiphase in early material. In an attempt to resolve this mystery, we have carried out systematic structural studies on a set of well-controlled samples with exact chemical stoichiometry K2−xFe4+xSe5 (x = 0–0.3) that are heat-treated at different temperatures. Using high-resolution synchrotron radiation X-ray diffraction, our investigations have determined the superconducting transition by focusing on the detailed temperature evolution of the crystalline phases. Our results show that superconductivity appears only in those samples that have been treated at high-enough temperature and then quenched to room temperature. The volume fraction of superconducting transition strongly depends on the annealing temperature used. The most striking result is the observation of a clear contrast in crystalline phase between the nonsuperconducting parent compound K2Fe4Se5 and the superconducting K2−xFe4+ySe5 samples. The X-ray diffraction patterned can be well indexed to the phase with I4/m symmetry in all temperatures investigated. However, we need two phases with similar I4/m symmetry but different parameters to best fit the data at a temperature below the Fe vacancy order temperature. The results strongly suggest that superconductivity in K2−xFe4+ySe5 critically depends on the occupation of Fe atoms on the originally empty 4d site.

Download Full-text

Investigation of Structural Formation of Starting Composition 2245 in the Bi-Pb-Sr-Ca-Cu-O System Superconductors

Journal of Solid State Physics ◽

10.1155/2014/716032 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7

Author(s):

Ashoka Nukkanahalli Venkataswamy ◽

George Thomas Chirayil ◽

Srinivasan Kannaiyan

Keyword(s):

Heat Treatment ◽

Volume Fraction ◽

X Ray Diffraction ◽

Structural Formation ◽

Major Phase ◽

X Ray ◽

Superconducting Volume Fraction ◽

Superconducting Compound ◽

First Time

Structural formation of Bi1.65Pb0.35Sr2Ca4Cu5Oy (2245 phase) superconducting compound was investigated by preparing the sample in a new matrix route. The phases formed at different intervals of heat treatment are monitored by X-ray diffraction studies. Bi-2212 phase was found to be the predominant phase till 20 hours of sintering at 850°C after which Bi-2223 phase was found to be the major phase. Traces of Ca2PbO4 were also noticed along with 2212 and 2223 phases. For the first time, the highest TC onset of 127 K with maximum superconducting volume fraction was observed for the sample sintered at 850°C for 30 hours in this preparation. Further sintering is found to deteriorate the TC onset value of the sample. There was no signature of the formation of 2234 or 2245 phase in this synthesis.

Download Full-text

The Influence of Ce-Doping on Structural and Superconducting Properties in Low-Density Bi1.6Pb0.4Sr2Ca2-xCexCu3Oy Superconductor

Materials Science Forum ◽

10.4028/www.scientific.net/msf.846.579 ◽

2016 ◽

Vol 846 ◽

pp. 579-585

Author(s):

M. Robaiah ◽

H. Azhan ◽

K. Azman ◽

S. Akmal Syamsyir ◽

I.N. Syuhaida ◽

...

Keyword(s):

Volume Fraction ◽

Xrd Analysis ◽

Zero Magnetic Field ◽

Weak Links ◽

Transport Critical Current Density ◽

Low Density ◽

Superconducting Properties ◽

X Ray Diffraction ◽

Solid State Method ◽

X Ray

The influences of cerium doped on low density Bi-2223 superconductor have been studied and this study examines the significant changes in the structural and superconducting properties. The nominal compositions of low density Bi1.6Pb0.4Sr2Ca2-xCexCu3Oy (where x =0.000, 0.025, 0.05, 0.1 and 0.2) ceramic superconductor were prepared by solid state method. The effects of different Ce doping levels on the superconductor structure and superconducting properties has been investigated by field emission scanning electron microscopy (FESEM), X-ray diffraction analysis (XRD), electrical resistance and transport critical current density (JC) measurements. The results show that TC zero and JC of the samples reduced gradually with the increase in the Ce addition. It has been observed that, the JC of low density Bi-2223 for Ce-free was measured to be 12.120 A/cm2 and 0.448 A/cm2 in x=0.025 at 60 K under zero magnetic field. As for XRD analysis showed the doping of Ce reduced the volume fraction of the 2223 phase and increased the volume fraction of the 2212 phase. FESEM results showed the surface morphology not homogenous and weak links between superconducting grains of the samples due to increase of the Ce doping.

Download Full-text

Changing the Static and Dynamic Lattice Effects for the Improvement of the Ionic Transport Properties Within the Argyrodite Li6PS5-xSexI

10.26434/chemrxiv.9807770.v1 ◽

2019 ◽

Author(s):

Roman Schlem ◽

Michael Ghidiu ◽

Sean Culver ◽

Anna-Lena Hansen ◽

Wolfgang Zeier

Keyword(s):

Ionic Conductivity ◽

Activation Barrier ◽

Parent Compound ◽

Ionic Transport ◽

X Ray Diffraction ◽

X Ray ◽

Lattice Effects ◽

Solid State Batteries ◽

All Solid State Batteries ◽

Pulse Echo

The lithium argyrodites Li6PS5X (X = Cl, Br, I) have been gaining momentum as candidates for electrolytes in all-solid-state batteries. While these materials have been well-characterized structurally, the influences of the static and dynamic lattice properties are not fully understood. Recent improvements to the ionic conductivity of Li6PS5I (which as a parent compound is a poor ionic conductor) via elemental substitutions have shown that a multitude of influences affect the ionic transport in the lithium argyrodites, and that even poor conductors in this class have room left for improvement.Here we explore the influence of isoelectronic substitution of sulfur with selenium in Li6PS5-xSexI. Using a combination of X-ray diffraction, impedance spectroscopy, Raman spectroscopy, and pulse-echo speed of sound measurements,we explore the influence of the static and dynamic lattice on the ionic transport. The substitution of S2-with Se2- broadens the diffusion pathways and structural bottlenecks, as well as leading to a softer more polarizable lattice, all of which lower the activation barrier and lead to an increase in the ionic conductivity. This work sheds light on ways to systematically understand and improve the functional properties of this exciting material family.

Download Full-text

Effect of the γ→ε Phase Transition on Transformation-Induced Plasticity (TRIP) of Nickel-Free High Nitrogen Steel at Low Temperatures

Metals ◽

10.3390/met11050710 ◽

2021 ◽

Vol 11 (5) ◽

pp. 710

Author(s):

Natalia Narkevich ◽

Yevgeny Deryugin ◽

Yury Mironov

Keyword(s):

Volume Fraction ◽

Tensile Load ◽

X Ray Diffraction ◽

High Nitrogen Steel ◽

Transformation Induced Plasticity ◽

X Ray ◽

Root Cause ◽

Nitrogen Steel ◽

Ε Phase ◽

Ε Martensite

The deformation behavior, mechanical properties, and microstructure of Fe-Cr-Mn-0.53%N austenitic stainless steel were studied at a temperature range of 77 up to 293 K. The dynamics of the steel elongation were non-monotonic with a maximum at 240–273 K, when peaks of both static atom displacements from their equilibrium positions in austenite and residual stresses in the tensile load direction were observed. The results of X-ray diffraction analysis confirmed that the only stress-induced γ→ε-martensite transformation occurred upon deformation (no traces of the γ→α′ one was found). In this case, the volume fraction of ε-martensite was about 2–3%. These transformation-induced plasticity (TRIP) patterns were discussed in terms of changes in the phase composition of steel as the root cause.

Download Full-text

Spark Plasma Sintering of Ti-4.5Al-3V-2Fe-2Mo (SP-700)

Materials Science Forum ◽

10.4028/www.scientific.net/msf.654-656.819 ◽

2010 ◽

Vol 654-656 ◽

pp. 819-822

Author(s):

Genki Kikuchi ◽

Hiroshi Izui ◽

Yuya Takahashi ◽

Shota Fujino

Keyword(s):

Spark Plasma Sintering ◽

Room Temperature ◽

Volume Fraction ◽

Titanium Boride ◽

Tensile Tests ◽

X Ray Diffraction ◽

X Ray ◽

Plasma Sintering ◽

Spark Plasma ◽

Tib2 Particles

In this study, we focused on the sintering performance of Ti-4.5Al-3V-2Mo-2Fe (SP-700) and mechanical properties of SP-700 reinforced with titanium boride (TiB/SP-700) fabricated by spark plasma sintering (SPS). TiB whiskers formed in titanium by a solid-state reaction of titanium and TiB2 particles were analyzed with scanning electron microscopy and X-ray diffraction. The TiB/SP-700 was sintered at temperatures of 1073, 1173, and 1273 K and a pressure of 70 MPa for 10, 30, and 50 min. The volume fraction of TiB ranged from 1.7 vol.% to 19.9 vol.%. Tensile tests of TiB/SP-700 were conducted at room temperature, and the effect of TiB volume fraction on the tensile properties was investigated.

Download Full-text