scholarly journals The Use of Curium as a Rare Earth Substitute in High Tc‐Related Compounds

1989 ◽  
Vol 169 ◽  
Author(s):  
L Soderholm ◽  
C.W. Williams ◽  
U. Welp
Keyword(s):  
Rare Earth ◽  
Magnetic Measurements ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray ◽  
Lattice Constants ◽  
Effective Moment ◽  
Free Ion ◽  
Related Compounds ◽  
Cu Ions

AbstractWe report the synthesis of Cm2CuO4. The lattice constants of this material, determined by x‐ray diffraction, show it to be a new member of the isostructural series R2CuO4 (R=Pr, Nd, Sm, Eu, and Gd). Analysis of magnetic measurements is consistent with a free‐ion effective moment for Cm3+, with no contribution to the susceptibility from Cu‐ions.

Composition and Lattice Constant Evaluation of the Garnet System (Dy, Gd)3Ga5O12

1972 ◽  
Vol 16 ◽  
pp. 177-185
Author(s):  
L. A. Moudy ◽  
S. B. Austerman
Keyword(s):  
Thin Film ◽  
Rare Earth ◽  
Lattice Constant ◽  
Direct Measurement ◽  
Magnetic Thin Film ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Matching ◽  
Lattice Constants ◽  
Constant Control

AbstractCompositional and lattice constant control of non-magnetic garnet substrates are required for suitable lattice matching with epitaxially deposited magnetic thin film. Suitable substrates for this purpose are the simple and mixed rare earth garnets. Lattice constants were obtained on Czochralski grown crystals by conventional x-ray diffraction powder techniques with a precision of ± .0005Å. An x-ray fluorescence method was developed to determine crystal composition with a precision of ± 0.5 percent. The precision with which a can be determined indirectly by x-ray fluorescence is ± 0.0082Å, which is comparable with that from direct measurement.

Two series of rare earth metal-rich ternary aluminium transition metallides – RE6Co2Al (RE=Sc, Y, Nd, Sm, Gd–Tm, Lu) and RE6Ni2.25Al0.75 (RE=Y, Gd–Tm, Lu)

2018 ◽  
Vol 73 (11) ◽  
pp. 927-942 ◽  
Author(s):  
Frank Stegemann ◽  
Oliver Janka
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Rare Earth Metal ◽  
Magnetic Measurements ◽  
Earth Metal ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Antiferromagnetic Ordering ◽  
Arc Melting

AbstractThe rare earth metal-rich cobalt and nickel aluminium compounds with the general compositions RE6Co2Al (RE=Sc, Y, Nd, Sm, Gd–Tm, Lu) and RE6Ni2.25Al0.75 (RE=Y, Gd–Tm, Lu) have been synthesised from the elements by arc-melting, followed by annealing. Single-crystal X-ray diffraction experiments on Y6Co2.02(1)Al0.98(1) (Ho6Co2Ga type; Immm; a=944.1(2), b=952.4(2), c=999.0(2) pm; wR2=0.0452, 1123 F2 values, 35 variables) and Y6Ni2.26(1)Al0.74(1) (Ho6Co2Ga type; Immm; a=938.30(5), b=959.45(5), c=996.05(6) pm; wR2=0.0499, 1131 F2 values, 35 variables) revealed that the compounds form solid solutions according to the general formula RE6(Co/Ni)2+xAl1−x with different homogeneity ranges. The compounds of the Ni series can be obtained in X-ray pure form only with the nominal composition RE6Ni2.25Al0.75. A significant increase of the U22 component of the anisotropic displacement parameters of the Co/Ni2 atoms (4g site) was observed that requires a description of the structure with a split-position model at RT. Further investigations by low temperature (90 K) single-crystal X-ray diffraction experiments of Y6Co2.02(1)Al0.98(1) showed a significant decrease of U22. Magnetic measurements were conducted on the X-ray pure members of the RE6Co2Al (RE=Y, Dy–Tm, Lu) series. Antiferromagnetic ordering was observed for the members with unpaired f electrons with Néel temperatures up to TN=48.0(1) K and two spin reorientations for Dy6Co2Al.

Magnetic properties of (Sr1.85Ln0.15)FeMoO6 with Ln = Sr, La, Ce, Pr, Nd, Sm and Eu

2011 ◽  
Vol 239-242 ◽  
pp. 3109-3112 ◽  
Author(s):  
Qin Zhang ◽  
Qing Wang ◽  
Zhen Cui Sun ◽  
Ke Yan Wang
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Ionic Radius ◽  
Single Phase ◽  
Magnetic Measurements ◽  
Rare Earth Ions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rare Earth Doped ◽  
The Eu

Rare-earth-doped compounds (Sr1.85Ln0.15)FeMoO6(Ln=Sr, La, Ce, Pr, Nd, Sm and Eu) have been prepared by solid-state reaction. Crystal structure and magnetic properties were investigated by means of X-ray diffraction and magnetic measurements. All the samples are single phase and belong to the I4/m space group. Due to the competing contributions of electron doping and steric effects, the unit-cell volume of the doped compounds changes slightly and does not vary systematically with the ionic radius of the rare-earth ions. The temperature dependence of the magnetization of (Sr1.85Ln0.15)FeMoO6indicates that the Curie temperature of the doped compounds has increased upon doping, except for the Eu-doped compound.

HIGH Tc SUPERCONDUCTIVITY AND SUBSTRUCTURE OF Bi-Sr-Ca-Cu-O SYSTEM

1988 ◽  
Vol 02 (02) ◽  
pp. 563-569 ◽  
Author(s):  
XING ZHU ◽  
SUNQI FENG ◽  
GUO LU ◽  
CHONGDE WEI ◽  
HANG ZHANG ◽  
...  
Keyword(s):  
Solid State Reaction Method ◽  
Main Phase ◽  
Nominal Composition ◽  
Chemical Compositions ◽  
Orthorhombic Symmetry ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray ◽  
Lattice Constants ◽  
Two Phases

Bi x Sr 1 Ca 1 Cu y O z(x, y=1, 2 or 3) high Tc superconductors were synthesized by solid state reaction method. There are two superconducting phases in Bi-Sr-Ca-Cu-O system: 110 K phase and 80 K phase. The relative portion of the two phases and the state of superconducting connection are closely related to chemical compositions and the conditions of processing. X-ray powder diffraction shows that there exists a main phase with orthorhombic symmetry in the samples of different compositions and conditions of processing. According to X-ray diffraction data, the lattice constants of the main phase in the sample of nominal composition Bi 1 Sr 1 Ca 1 Cu 2 O z have been determined as aο=5.44Å, bο=5.35Å and co=30.66Å. Electron diffraction shows complicated modulation structure along b− and c− axes. High resolution image along [001] zone axis indicates the modulation structure along b− axis.

ON THE LATTICE INSTABILITY BETWEEN 100 AND 300 K OF YBa2Cu3O7−y HIGH Tc SUPERCONDUCTING CERAMIC

1989 ◽  
Vol 03 (10) ◽  
pp. 1581-1595 ◽  
Author(s):  
Y. HE ◽  
J. XIANG ◽  
S. LIN ◽  
Z. LIU ◽  
L. CAI ◽  
...  
Keyword(s):  
Specific Heat ◽  
Oxygen Vacancies ◽  
X Ray Diffraction ◽  
Lattice Instability ◽  
High Tc ◽  
X Ray ◽  
Lattice Constants ◽  
Ultrasonic Measurements ◽  
Tetragonal Phase Transition ◽  
Superconducting Ceramic

The lattice instability of YBa 2 Cu 3 O 7−y superconducting ceramic between 100 and 300 K has been studied by means of ultrasonic measurements, TEM study, X-ray diffraction experiments, thermal analysis and specific heat measurements for samples from different laboratories. It was shown that there are anomalous changes in lattice constants near 250 K, 170 K and 130 K, together with specific heat anomalies near this temperature region, which is consistent with the longitudinal and transverse ultrasonic results. Such anomalies are caused by an intrinsic lattice instability related to the ordering readjustments of the oxygen vacancies, which was confirmed by the observed tendency of reversible orthohombic to tetragonal phase transition near 170 K.

Rapidly quenched Bi-containing high Tc superconducting oxide compositions

1989 ◽  
Vol 4 (6) ◽  
pp. 1330-1338 ◽  
Author(s):  
K. Nassau ◽  
A. E. Miller ◽  
E. M. Gyorgy ◽  
T. Siegrist
Keyword(s):  
Copper Oxide ◽  
Oxide Layer ◽  
Short Range ◽  
Short Range Order ◽  
Magnetic Measurements ◽  
Anomalous Behavior ◽  
Oxygen Absorption ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray

Twin roller quenching from the melt at cooling rates of ∼107 K s−1 was used on several Bi-containing high Tc compositions. Pure glass was obtained in most compositions and the route of crystallization was studied by differential thermal and thermogravimetric analysis, x-ray diffraction, and magnetic measurements. Heating of the glasses produced poorly crystallized short-range-order-only as determined by x-ray diffraction, despite passing through several exotherms, some of which were very strong. This anomalous behavior deserves further investigation. On heating to higher temperatures the expected double-copper-oxide-layer high Tc phase formed sluggishly via intermediate CuBi2O4 and/or single-copper-oxide-layer Bi2(Sr, Cu)2CuO4 phases. Considerable oxygen absorption of about 0.5 O per Cu occurs during these steps, peaking at about 680 °C; some of this oxygen is lost again by the time the high Tc phase forms just below the melting point.

THE EFFECT OF 5% Sb DOPING ON HIGH Tc SUPERCONDUCTIVITY IN (Bi, Pb)2Sr2Ca2Cu3Oy COMPOUND

2003 ◽  
Vol 17 (05n06) ◽  
pp. 199-208 ◽  
Author(s):  
SAADAT A. SIDDIQI ◽  
BILQUEES AKHTAR ◽  
IJAZ M. GHAURI
Keyword(s):  
Superconducting Phase ◽  
X Ray Diffraction ◽  
High Tc ◽  
Density Measurements ◽  
X Ray ◽  
Lattice Constants ◽  
Sintering Time ◽  
Maximum Value ◽  
Sb Doping ◽  
Two Phases

The effect of a small amount of Sb doping (5%) on the formation of the high temperature superconducting phase has been investigated on the Bi 1.5 Pb 0.5 Sr 2 Ca 2 Cu 3 O y compound. It is observed that at 860°C the T c zero [Formula: see text] value depends on the sintering time. It first increases to a maximum value of 96 K and then decreases to a stable lowest value of 88 K. The samples have been characterized by X-ray diffraction (XRD), four probe electrical resistance and current density measurements. The XRD revealed the presence of two phases: an orthorhombic high-T c 2223 phases with lattice constants a = 5.395 Å, b = 5.508 Å, c = 37.0422 Å and another tetragonal low-T c 2212 phase with lattice constants a = b = 5.419 Å, c = 30.832 Å.

scholarly journals Synthesis and Physical Properties of Iridium-Based Sulfide Ca1−xIr4S6(S2) [x = 0.23–0.33]

2022 ◽  
Vol 3 (1) ◽  
pp. 41-52
Author(s):  
Michael Vogl ◽  
Martin Valldor ◽  
Roman Boy Piening ◽  
Dmitri V. Efremov ◽  
Bernd Büchner ◽  
...  
Keyword(s):  
Density Functional ◽  
Magnetic Measurements ◽  
X Ray Diffraction ◽  
Metallic Behavior ◽  
Functional Theory ◽  
X Ray ◽  
Lattice Constants ◽  
The Density Functional Theory ◽  
Xrd Techniques

We present the synthesis and characterization of the iridium-based sulfide Ca1−xIr4S6(S2). Quality and phase analysis were conducted by means of energy-dispersive X-ray spectroscopy (EDXS) and powder X-ray diffraction (XRD) techniques. Structure analysis reveals a monoclinic symmetry with the space group C 1 2/m 1 (No. 12), with the lattice constants a = 15.030 (3) Å, b = 3.5747 (5) Å and c = 10.4572 (18) Å. Both X-ray diffraction and EDXS suggest an off-stoichiometry of calcium, leading to the empirical composition Ca1−xIr4.0S6(S2) [x = 0.23–0.33]. Transport measurements show metallic behavior of the compound in the whole range of measured temperatures. Magnetic measurements down to 1.8 K show no long range order, and Curie–Weiss analysis yields θCW = −31.4 K, suggesting that the compound undergoes a magnetic state with short range magnetic correlations. We supplement our study with calculations of the band structure in the framework of the density functional theory.

scholarly journals Crystal Chemical Relations in the Shchurovskyite Family: Synthesis and Crystal Structures of K2Cu[Cu3O]2(PO4)4 and K2.35Cu0.825[Cu3O]2(PO4)4

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 807
Author(s):  
Ilya V. Kornyakov ◽  
Sergey V. Krivovichev
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Structural Complexity ◽  
Crystal Chemical ◽  
X Ray Diffraction ◽  
Complexity Measures ◽  
X Ray ◽  
The Family ◽  
Similarities And Differences ◽  
Related Compounds

Single crystals of two novel shchurovskyite-related compounds, K2Cu[Cu3O]2(PO4)4 (1) and K2.35Cu0.825[Cu3O]2(PO4)4 (2), were synthesized by crystallization from gaseous phase and structurally characterized using single-crystal X-ray diffraction analysis. The crystal structures of both compounds are based upon similar Cu-based layers, formed by rods of the [O2Cu6] dimers of oxocentered (OCu4) tetrahedra. The topologies of the layers show both similarities and differences from the shchurovskyite-type layers. The layers are connected in different fashions via additional Cu atoms located in the interlayer, in contrast to shchurovskyite, where the layers are linked by Ca2+ cations. The structures of the shchurovskyite family are characterized using information-based structural complexity measures, which demonstrate that the crystal structure of 1 is the simplest one, whereas that of 2 is the most complex in the family.

scholarly journals High Pressure X-ray Diffraction as a Tool for Designing Doped Ceria Thin Films Electrolytes

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 724
Author(s):  
Sara Massardo ◽  
Alessandro Cingolani ◽  
Cristina Artini
Keyword(s):  
Thin Films ◽  
High Pressure ◽  
Rare Earth ◽  
Ionic Conductivity ◽  
Bulk Material ◽  
Threshold Temperature ◽  
Doped Ceria ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rare Earth Doped

Rare earth-doped ceria thin films are currently thoroughly studied to be used in miniaturized solid oxide cells, memristive devices and gas sensors. The employment in such different application fields derives from the most remarkable property of this material, namely ionic conductivity, occurring through the mobility of oxygen ions above a certain threshold temperature. This feature is in turn limited by the association of defects, which hinders the movement of ions through the lattice. In addition to these issues, ionic conductivity in thin films is dominated by the presence of the film/substrate interface, where a strain can arise as a consequence of lattice mismatch. A tensile strain, in particular, when not released through the occurrence of dislocations, enhances ionic conduction through the reduction of activation energy. Within this complex framework, high pressure X-ray diffraction investigations performed on the bulk material are of great help in estimating the bulk modulus of the material, and hence its compressibility, namely its tolerance toward the application of a compressive/tensile stress. In this review, an overview is given about the correlation between structure and transport properties in rare earth-doped ceria films, and the role of high pressure X-ray diffraction studies in the selection of the most proper compositions for the design of thin films.

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