INVESTIGATION OF SUPERCONDUCTIVITY IN Y–Sr–Cu–O

1990 ◽  
Vol 04 (03) ◽  
pp. 195-199 ◽  
Author(s):  
R. SURYANARAYANAN ◽  
S. B. BALIGA ◽  
A. L. JAIN ◽  
O. GOROCHOV
Keyword(s):  
Magnetic Susceptibility ◽  
Nominal Composition ◽  
Ferromagnetic Transition ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Higher Temperature

Preparation, X-ray diffraction (XRD), resistivity (ρ) and magnetic susceptibility (χ) of YSrCuO y (nominal composition) synthesized at 1200°C are reported. XRD data indicate more than one phase. Zero resistivity is observed at 72 K. The field cooled χ indicates a superconducting transition at 68 K and also an anti-ferromagnetic transition at 15 K which could be due to Y 2 Cu 2 O 5. These data confirm the earlier observations of Wu et al.5 who have, however, observed a higher T c at 85 K which could be due to a higher temperature used for synthesis.

scholarly journals X-Ray Powder Diffraction Study on the MgB2 Superconductor Reacted with Nano-SiC: The Effects of Sintering Temperature

2010 ◽  
Vol 173 ◽  
pp. 78-83
Author(s):  
Kwee Yong Tan ◽  
Tan Kim Lee ◽  
Lim Kean Pah ◽  
Shaari Abdul Halim ◽  
Tan Kar Ban ◽  
...  
Keyword(s):  
Phase Formation ◽  
Sintering Temperature ◽  
Lattice Parameter ◽  
Primary Phase ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Higher Temperature ◽  
Addition Level

SiC added MgB2 polycrystalline samples were synthesized at low (650°C) and high (850°C) temperatures in order to study the sintering effect on the phase formation and superconducting properties. The MgB2 bulks with additions of 0wt%, 1wt%, 3wt% and 5wt% SiC were studied with powder X-ray diffraction technique. We observed that MgB2 remained as the primary phase for both sintering temperatures in all samples with the presence of MgO and Mg2Si as the main impurities. Some diffraction peaks associated with unreacted SiC is also noticeable. The relative intensity of the Mg2Si peaks was found to decrease in samples sintered at higher temperature. Temperature dependent magnetic moment measurements showed that the superconducting transition temperature, Tc decreases as the SiC addition level increases while lower sintering temperature degrades Tc to a greater extent. The changes in the physical properties is discussed based on the results of phase formation, full width half maximum (FWHM), lattice parameter and crystallite size.

Antiferromagnetic behavior in Y–Ba–(Cu1−xScx)–O

1989 ◽  
Vol 4 (3) ◽  
pp. 467-469 ◽  
Author(s):  
A. Chakraborty ◽  
X. D. Chen ◽  
F. Zuo ◽  
B. R. Patton ◽  
J. R. Gaines ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Composition Range ◽  
Second Phase ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Susceptibility Study ◽  
New Phase ◽  
Antiferromagnetic Behavior

We report the results on x-ray diffraction and magnetic susceptibility study of Y–Ba–(Cu1−xScx)–O. The materials were prepared in a stoichiometry corresponding to Y1Ba2(Cu1−xScx)3O7. Although x-ray analysis reveals the increasing presence of a subtle second phase with increasing Sc content, the superconducting transition temperature and resistivity did not change substantially in the composition range 0.0  x ≤ 0.15. In contrast, the magnetic susceptibility studies showed dramatic changes. Although Sc3+ has no spin by itself, an enhanced paramagnetic Curie susceptibility was observed above Tc with a moment of 1.5 μB per Sc. At 16 K a sharp cusp is observed in the temperature dependent susceptibility corresponding to the onset of a three-dimensionally ordered antiferromagnetic state. These results are discussed in terms of an additional previously unreported phase of Y–Ba–(Cu–Sc)–O that has an antiferromagnetic Néel temperature of 16 K. For composition of x = 1.0, a new phase is formed which is nonmagnetic.

Effect of Temperature on La1.85Sr0.15CuO4 Single Crystal Growth by Floating Zone Method

2007 ◽  
Vol 546-549 ◽  
pp. 1897-1900 ◽  
Author(s):  
X.Q. Xiang ◽  
J.F. Qu ◽  
Y.Q. Zhang ◽  
X.L. Lu ◽  
X.G. Li
Keyword(s):  
Crystal Growth ◽  
Single Crystal ◽  
Effect Of Temperature ◽  
Superconducting Transition ◽  
Floating Zone ◽  
X Ray Diffraction ◽  
Zone Method ◽  
Floating Zone Method ◽  
X Ray ◽  
Higher Temperature

Superconducting single crystals of La1.85Sr0.15CuO4 have been grown at various temperatures without single crystal seeds by the traveling-solvent floating-zone method. In order to avoid the formation of bubbles during the crystal growth process, a flowing atmosphere of 2 atm oxygen or 1 atm air was applied in different temperature range. It was found that the crystal quality could be improved by raising the growth temperature in a certain range, and the orientation changed from (110) to (100) at higher temperature. X-ray diffraction results showed that the full-width at half-maximum of the best as-prepared crystal was 0.086°. The crystals grown in 2 atm oxygen showed a superconducting transition temperature (Tc) of 37.3 K, while the crystals grown in floating air showed a Tc of about 35 K and it could be improved to 36.5 K by annealing in flowing oxygen.

SUPERCONDUCTIVITY IN Bi-Sr-Ca-Mg-Cu-OXIDE

1991 ◽  
Vol 05 (11) ◽  
pp. 771-777 ◽  
Author(s):  
A.Y. KHAN ◽  
M. MOHAMMAD ◽  
M. SHAHNAZ ◽  
S.K. HASNAIN
Keyword(s):  
Magnetic Susceptibility ◽  
Electrical Resistance ◽  
Meissner Effect ◽  
Superconducting Phase ◽  
Partial Substitution ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
Minor Phase ◽  
X Ray ◽  
A Minor

A Mg -substituted material with nominal composition Bi 2 Sr 2 Ca 3 Mg 2 Cu 6 O x, prepared by partial substitution of Ca by isovalent Mg in the 2256 composition of Bi-Sr-Ca-Cu-O , has been studied by the measurements of electrical resistance, magnetic susceptibility and X-ray diffraction pattern. Results show the existence of a superconducting phase with onset T c at 112.5±1 K along with a minor phase with onset T c =88 K . The material retained superconducting characteristics (Meissner effect and T c onset ) even after a period of six months.

scholarly journals Effect of sintering time on Bi1.6Pb0.4Sr1.8Ba0.2Ca2Cu3O10+? compound quenched in air and liquid nitrogen

2014 ◽  
Vol 11 (2) ◽  
pp. 713-717
Author(s):  
Baghdad Science Journal
Keyword(s):  
Liquid Nitrogen ◽  
Solid State Reaction Method ◽  
Nominal Composition ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray ◽  
Sintering Time ◽  
High Tc Phase ◽  
Two Phases

High temperature superconductor with nominal composition Bi1.6Pb0.4Sr1.8Ba0.2Ca2 Cu3O10+? was prepared by solid state reaction method. Two sets of samples have been prepared .The first one was quenched in air; the second set was quenched in liquid nitrogen. X-ray diffraction analyses showed an orthorhombic structure with two phases, high –Tc phase (2223) and low-Tc phase (2212) in addition to that impure phase was found. It has been observed that quenched in air samples display a sharp superconducting transition and a higher-Tc phase than that of the quenched in liquid nitrogen samples.

Superconducting and Magnetic Properties of (Ru1-xNbx)Sr2(Eu1.5Ce0.5)Cu2Oz

2003 ◽  
Vol 17 (18n20) ◽  
pp. 3682-3687 ◽  
Author(s):  
H. K. Lee ◽  
Y. C. Kim
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Transition Temperature ◽  
Meissner Effect ◽  
Internal Field ◽  
Electric Transport ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vortex Phase

The ( Ru 1-x Nb x) Sr 2( Eu 1.5 Ce 0.5) Cu 2 O z(0 ≤ x ≤ 0.5) compounds have been synthesized and characterized by X-ray diffraction, electric transport, and magnetic susceptibility measurements. We find that there is no significant change in the superconducting transition temperature when Nb is substituted for Ru up to x = 0.5. Unlike RuSr 2( Eu 1.5 Ce 0.5) Cu 2 O z, bulk Meissner effect is observed in the field-cooled magnetization measurements of the Nb doped samples. The experimental results are discussed in conjunction with a reduction of the internal field caused by the Nb substitution for Ru, based on the spontaneous vortex phase interpretation.

Electron Microscopy/Diffraction Study of the Ternary Mn-Er-S System

1990 ◽  
Vol 48 (1) ◽  
pp. 76-77
Author(s):  
A. R. Landa Canovas ◽  
L.C. Otero Diaz ◽  
T. White ◽  
B.G. Hyde
Keyword(s):  
Electron Microscopy ◽  
Gas Flow ◽  
Graphite Crucible ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
Alumina Crucible ◽  
X Ray ◽  
Intermediate Phases ◽  
Twin Band ◽  
Ar Gas

X-Ray diffraction revealed two intermediate phases in the system MnS+Er2S3,:MnEr2S4= MnS.Er2S3, and MnEr4S7= MnS.2Er2S3. Their structures may be described as NaCl type, chemically twinned at the unit cell level, and isostructural with CaTi2O4, and Y5S7 respectively; i.e. {l13} NaCl twin band widths are (4,4) and (4,3).The present study was to search for structurally-related (twinned B.) structures and or possible disorder, using the more sensitive and appropiate technigue of electron microscopy/diffraction.A sample with nominal composition MnEr2S4 was made by heating Mn3O4 and Er2O3 in a graphite crucible and a 5% H2S in Ar gas flow at 1500°C for 4 hours. A small amount of this material was thenannealed, in an alumina crucible, contained in sealed evacuated silica tube, for 24 days at 1100°C. Both samples were studied by X-ray powder diffraction, and in JEOL 2000 FX and 4000 EX microscopes.

scholarly journals Impact of high temperatures on aluminoceladonite studied by Mössbauer, Raman, X-ray diffraction and X-ray photoelectron spectroscopy

2021 ◽  
Author(s):  
Mariola Kądziołka-Gaweł ◽  
Maria Czaja ◽  
Mateusz Dulski ◽  
Tomasz Krzykawski ◽  
Magdalena Szubka
Keyword(s):  
Photoelectron Spectroscopy ◽  
Integral Intensity ◽  
Photoelectron Spectra ◽  
X Ray Diffraction ◽  
Structural Reorganization ◽  
Oh Groups ◽  
X Ray ◽  
Al Content ◽  
Integral Intensity Ratio ◽  
Higher Temperature

AbstractMössbauer, Raman, X-ray diffraction and X-ray photoelectron spectroscopies were used to examine the effects of temperature on the structure of two aluminoceladonite samples. The process of oxidation of Fe2+ to Fe3+ ions started at about 350 °C for the sample richer in Al and at 300 °C for the sample somewhat lower Al-content. Mössbauer results show that this process may be associated with dehydroxylation or even initiate it. The first stage of dehydroxylation takes place at a temperature > 350 °C when the adjacent OH groups are replaced with a single residual oxygen atom. Up to ~500 °C, Fe ions do not migrate from cis-octahedra to trans-octahedra sites, but the coordination number of polyhedra changes from six to five. This temperature can be treated as the second stage of dehydroxylation. The temperature dependence on the integral intensity ratio between bands centered at ~590 and 705 cm−1 (I590/I705) clearly reflects the temperature at which six-coordinated polyhedra are transformed into five-coordinated polyhedra. X-ray photoelectron spectra obtained in the region of the Si2p, Al2p, Fe2p, K2p and O1s core levels, highlighted a route to identify the position of Si, Al, K and Fe cations in a structure of layered silicates with temperature. All the measurements show that the sample with a higher aluminum content and a lower iron content in octahedral sites starts to undergo a structural reorganization at a relatively higher temperature than the less aluminum-rich sample does. This suggests that iron may perform an important role in the initiation of the dehydroxylation of aluminoceladonites.

Study of Low-Grade Nickel Laterite Processing Using Palm Shell Charcoal as Reductant

2020 ◽  
Vol 1000 ◽  
pp. 436-446
Author(s):  
Bambang Suharno ◽  
Nolzha Primadha Ilman ◽  
Achmad Shofi ◽  
Deni Ferdian ◽  
Fajar Nurjaman
Keyword(s):  
Sodium Sulfate ◽  
Selective Reduction ◽  
Reduction Process ◽  
Low Grade ◽  
X Ray Diffraction ◽  
X Ray ◽  
Palm Shell ◽  
Higher Temperature ◽  
Nickel Grade

This study was conducted to investigate the effect of palm shell charcoal reductant in the selective reduction of nickel ore with the addition of additive at various temperatures and times. In this present work, 10 wt. % of sodium sulfate as additive and 5, 10, 15 wt. % of palm shell charcoal as reductants were used. The reduction of nickel ore was performed at 950oC, 1050oC, and 1150oC for 60, 90, and 120 minutes. A wet magnetic separation method was then carried out to separate the concentrates and tailings. Characterization of reduced ore was performed by X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) with Energy Dispersive X-ray Spectroscopy (EDS), while the composition of ferronickel in concentrate was identified by X-Ray Fluorescence (XRF). The result showed that the higher temperature reduction, the higher of nickel grade, and its recovery at the concentrate. Nevertheless, the longer reduction time and the more reductant in nickel ore lowering the nickel grade and its recovery in the concentrate. The optimum condition in this selective reduction process was obtained with the addition of 5 wt. % of reductant and 10 wt. % of sodium sulfate in nickel ore, which was reduced at 1150oC for 60 minutes. It resulted in 4.60% and 73.23% for nickel grade and its recovery, respectively.

Ternary Antimonides RE4T7Sb6 (RE=Gd–Lu; T =Ru, Rh) with Cubic U4Re7Si6-type Structure

2013 ◽  
Vol 68 (9) ◽  
pp. 971-978 ◽  
Author(s):  
Inga Schellenberg ◽  
Ute Ch. Rodewald ◽  
Christian Schwickert ◽  
Matthias Eul ◽  
Rainer Pöttgen
Keyword(s):  
Magnetic Susceptibility ◽  
Single Crystal ◽  
Magnetic Moment ◽  
Induction Furnace ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Antiferromagnetic Ordering ◽  
Arc Melting ◽  
Intermediate Valent

The ternary antimonides RE4T7Sb6 (RE=Gd-Lu; T =Ru, Rh) have been synthesized from the elements by arc-melting and subsequent annealing in an induction furnace. The samples have been characterized by powder X-ray diffraction. Four structures were refined on the basis of single-crystal X-ray diffractometer data: U4Re7Si6 type, space group Im3m with a=862.9(2) pm, wR2=0.0296, 163 F2 values for Er4Ru7Sb6; a=864.1(1) pm, wR2=0.1423, 153 F2 values for Yb4Ru7Sb6; a=872.0(2) pm, wR2=0.0427, 172 F2 values for Tb4Rh7Sb6; and a=868.0(2) pm, wR2=0.0529, 154 F2 values for Er4Rh7Sb6, with 10 variables per refinement. The structures have T1@Sb6 octahedra and slightly distorted RE@T26Sb6 cuboctahedra as building units. The distorted cuboctahedra are condensed via all trapezoidal faces, and this network leaves octahedral voids for the T1 atoms. The ruthenium-based series of compounds was studied by temperature-dependent magnetic susceptibility measurements. Lu4Ru7Sb6 is Pauli-paramagnetic. The antimonides RE4Ru7Sb6 with RE=Dy, Ho, Er, and Tm show Curie-Weiss paramagnetism. Antiferromagnetic ordering occurs at 10.0(5), 5.1(5) and 4.0(5) K for Dy4Ru7Sb6, Ho4Ru7Sb6 and Er4Ru7Sb6, respectively, while Tm4Ru7Sb6 remains paramagnetic. Yb4Ru7Sb6 is an intermediate-valent compound with a reduced magnetic moment of 3.71(1) μB per Yb as compared to 4.54 μB for a free Yb3+ ion

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