Critical Current Properties of Hg(Re)1223 Single Crystals with Various Oxygen Content

2001 ◽  
Vol 689 ◽  
Author(s):  
S. Ueda ◽  
J. Shimoyama ◽  
T. Sato ◽  
S. Horii ◽  
K. Otzschi ◽  
...  
Keyword(s):  
Single Crystals ◽  
Critical Current ◽  
Single Phase ◽  
Magnetic Hysteresis ◽  
Maximum Size ◽  
Peak Effect ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Difference ◽  
Second Peak

ABSTRACTHigh quality single crystals of Hg(Re)1223 were grown by the flux method using BaZrO3 crucible, which is stable against molten Ba-Cu-O. The maximum size of the obtained crystal was 1 × 1.1 × 0.1mm3 in dimension. X-ray diffraction analysis revealed that grown crystals are of Hg(Re)1223 single phase with c0 = 15.7 å. In the magnetic hysteresis curves for post-annealed Hg(Re)1223 single crystals under H // c, large second peak effect was found with steep increase of magnetization at approximately 2∼3kOe independent of temperature. The peak field systematically increased with a decrease of temperature, suggesting generation of field-induced pinning. Critical current density and irreversibility field of single crystals were dependent on synthesis batch, possibly due to the difference in resulting concentration of Re, while postannealing under various conditions did not affect largely for critical current properties. Irreversibility lines of the Hg(Re)1223 single crystals locate at higher fields than that of Re-free Hg1223. This suggests that electromagnetic anisotropy is reduced by Re-doping, which is consistent with the recent results on the resistive anisotropy in the normal state.

scholarly journals Mn-Induced Thermal Stability of L10 Phase in Fept Magnetic Nanoscale Ribbons

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1278
Author(s):  
Alina Daniela Crisan ◽  
Aurel Leca ◽  
Dan Pantelica ◽  
Ioan Dan ◽  
Ovidiu Crisan
Keyword(s):  
Rare Earth ◽  
Single Phase ◽  
Permanent Magnets ◽  
Magnetic Hysteresis ◽  
Ternary Alloys ◽  
Large Temperature ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Operation Conditions

Magnetic nanoscale materials exhibiting the L10 tetragonal phase such as FePt or ternary alloys derived from FePt show most promising magnetic properties as a novel class of rare earth free permanent magnets with high operating temperature. A granular alloy derived from binary FePt with low Pt content and the addition of Mn with the nominal composition Fe57Mn8Pt35 has been synthesized in the shape of melt-spun ribbons and subsequently annealed at 600 °C and 700 °C for promoting the formation of single phase, L10 tetragonal, hard magnetic phase. Proton-induced X-ray emission spectroscopy PIXE has been utilized for checking the compositional effect of Mn addition. Structural properties were analyzed using X-ray diffraction and diffractograms were analyzed using full profile Rietveld-type analysis with MAUD (Materials Analysis Using Diffraction) software. By using temperature-dependent synchrotron X-ray diffraction, the disorder–order phase transformation and the stability of the hard magnetic L10 phase were monitored over a large temperature range (50–800 °C). A large interval of structural stability of the L10 phase was observed and this stability was interpreted in terms of higher ordering of the L10 phase promoted by the Mn addition. It was moreover found that both crystal growth and unit cell expansion are inhibited, up to the highest temperature investigated (800 °C), proving thus that the Mn addition stabilizes the formed L10 structure further. Magnetic hysteresis loops confirmed structural data, revealing a strong coercive field for a sample wherein single phase, hard, magnetic tetragonal L10 exists. These findings open good perspectives for use as nanocomposite, rare earth free magnets, working in extreme operation conditions.

A SDUTY OF SUPERCONDUCTING OXIDE Y-Ba-Cu-Sn-O

1987 ◽  
Vol 01 (02) ◽  
pp. 277-280 ◽  
Author(s):  
Xin Jin ◽  
Huimin Shao ◽  
Guiqin Wang ◽  
Mu Lu ◽  
Hanhe Zhang ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Magnetic Hysteresis ◽  
X Ray Diffraction ◽  
X Ray

A high-Tc superconductor YBa2Cu3 Snx07+z was characterized. We observed the existence about 90K superconductivity in variety of compositions. The samples were examined by x-ray diffraction , Mössbauer, SEM and EDS. Their structure are still ABO3 perovskite but part of Cu atoms are displaced by Sn. It was observed that when the x increased the critical current density were increased based on the measurements of magnetic hysteresis.

Comparative Study on Mn-Zn Ferrites by One-Step Synthesis and Conventional Two-Step Synthesis

2010 ◽  
Vol 177 ◽  
pp. 260-263 ◽  
Author(s):  
Qing Kai Xing ◽  
Zhi Jian Peng ◽  
Xiu Li Fu ◽  
Zhi Qiang Fu ◽  
Cheng Biao Wang ◽  
...  
Keyword(s):  
Magnetic Hysteresis ◽  
Initial Permeability ◽  
Synthesis Methods ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Magnetic Performance ◽  
One Step ◽  
The Difference ◽  
The One

Mn-Zn ferrites doped with Cr3+ were prepared by “one-step synthesis” and conventional two-step synthesis methods, respectively. Their phase compositions and microstructures were characterized by X-ray diffraction and scanning electron microscopy, respectively. And their magnetic magnetic performance, such as saturation magnetization (Ms), magnetic hysteresis, initial permeability μi and power loss were comparatively investigated by vibrating sample magnetometer. It was observed that the difference of magnetic performance of the samples prepared by both methods is little. The similar performance of both methods makes the “one-step synthesis” especially attractive for application when considering energy economization.

Growth and Facet Orientations in Single-Phase TiAl Single Crystals

1994 ◽  
Vol 364 ◽  
Author(s):  
R. Mahapatra ◽  
H. Lin ◽  
D. P. Pope ◽  
Y. T. Chou
Keyword(s):  
Crystal Growth ◽  
Single Crystals ◽  
Single Phase ◽  
Tial Alloy ◽  
Solidification Rate ◽  
Floating Zone ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electron Backscattering

AbstractSingle crystals of single-phase TiAl alloy (Ti-56 at. % Al) have been grown at lOmm/h solidification rate in an ASGAL FZ-SS35W Optical Floating Zone Furnace. The orientations of the resulting single crystals have been determined using the Laue X-ray diffraction, and Electron Backscattering Pattern (EBSP) methods. A correlation between orientations of the crystal growth and grown-in facets has been established.

THE XRD STUDY OF THE EFFECT OF SLIGHT CHANGE IN STRUCTURE ON THE SUPERCONDUCTIVITY OF Y-Ba-Cu-O SYSTEM MATERIAL

1987 ◽  
Vol 01 (07n08) ◽  
pp. 289-293 ◽  
Author(s):  
WANG HUAQIN ◽  
ZHANG SHIYUAN ◽  
JIN TONGZHENG ◽  
HAN SHIYING ◽  
QIU DIRONG ◽  
...  
Keyword(s):  
Single Phase ◽  
Crystal Symmetry ◽  
Epr Spectra ◽  
Processing Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Xrd Study ◽  
The Difference ◽  
Diffraction Patterns ◽  
Flowing Oxygen

In this paper the differences in diffraction intensities from some crystal planes in the X-ray diffraction patterns of high Tc Y-Ba-Cu-O system superconductors prepared by different processing conditions and the difference among various structure cells in references are interpreted using computer fitting. The results suggest that there exists two structure cells in the single phase YBa2Cu3O7−x samples. Both structure cells have the same crystal symmetry and almost the same lattice parameters, a=3.821Å, b=3.892Å and c=11.676Å, but the different distortion degree of Cu2-O plane. According to EPR spectra measured on the same samples, it is considered that the improvement of superconductivity for the samples prepared by two-step annealing in flowing oxygen may be related to concentration of the structure cell with more serious distortion on the Cu2-O plane.

Syntheses and Crystal Structures of Sr7H12X2 (X = Cl, Br)

2008 ◽  
Vol 63 (5) ◽  
pp. 513-518 ◽  
Author(s):  
Olaf Reckeweg ◽  
Jay C. Molstad ◽  
Scott Levy ◽  
Constantin Hoch ◽  
Francis J. DiSalvo
Keyword(s):  
Stainless Steel ◽  
Single Crystal ◽  
Single Crystals ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
The Difference ◽  
Difference Fourier ◽  
New Compounds

Dichroic, pink to blue single crystals of Sr7H12Cl2 and Sr7H12Br2 were obtained by reacting Sr with SrX2 or NaX and NaNH2 or NH4X (X = Cl, Br) as hydrogen sources in a Na melt at 900 °C for 12 h in silica-jacketed stainless-steel or Ta ampoules. The crystal structures of the new compounds were determined by means of single crystal X-ray diffraction. Both title compounds crystallize isotypically to Ba7Cl2F12 in the hexagonal space group P6̅ (no. 174) with the lattice parameters a = 998.06(3), c = 392.84(3) pm for Sr7H12Cl2 and a = 1004.62(3), c = 399.68(3) pm for Sr7H12Br2. The hydride positions taken from the difference Fourier map agree with those of the fluorides of the isotypic compound Ba7F12Cl12. The validity of our structural results is corroborated by EUTAX calculations and the comparison to SrH2, SrX2 and SrHX.

Ferroelectricity in SrTiO3 Ceramics Induced by Pr Doping

2004 ◽  
Vol 848 ◽  
Author(s):  
A. Durán ◽  
E. Martínez ◽  
J. Mata ◽  
J. Heiras ◽  
X. Solans ◽  
...  
Keyword(s):  
Single Phase ◽  
Temperature Differential ◽  
X Ray Diffraction ◽  
Ionic Radii ◽  
Ferroelectric State ◽  
X Ray ◽  
The Difference ◽  
Diffraction Patterns ◽  
A Site ◽  
Srtio3 Ceramics

ABSTRACTFerroelectricity was induced in SrTiO3 by the Sr exchange for Pr ion in the A site of the perovskite ABO3-type structure. X-ray diffraction patterns show single phase crystalline structure in the SrxPr1-xTiO3 compound for x=0, 0.025, 0.050, 0.075 and 0.1 compositions. Rietveld refinement shows that the unit cell volume decreases with the increasing of Pr content as a consequence of the difference between Sr/Pr ionic radii. Furthermore, high-temperature differential thermoanalysis (DTA) displays a small anomaly at about 118 °C which is probably due to the Pr ion producing a distortion of the perovskite structure via an off-center site. This deformation in the lattice induces a measurable polar behavior of the solid solution. Dielectric permittivity (ε vs T) measurements display a well defined peak at about 238 °C. Furthermore, a well defined hysteresis loop at 30 °C with a remnant polarization that tends to decrease with increasing Pr concentration is observed. Both experimental results confirm the ferroelectric state induced by the Pr ion.

Antiphase Boundaries in Ordered Ni3FE Crystals

1969 ◽  
Vol 27 ◽  
pp. 62-63
Author(s):  
Y. H. Liu
Keyword(s):  
Domain Size ◽  
Antiphase Domain ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hardening Mechanism ◽  
Superlattice Structure ◽  
Disordered Phase ◽  
Domain Boundaries ◽  
Atomic Scattering ◽  
The Difference

Ordered Ni3Fe crystals possess a LI2 type superlattice similar to the Cu3Au structure. The difference in slip behavior of the superlattice as compared with that of a disordered phase has been well established. Cottrell first postulated that the increase in resistance for slip in the superlattice structure is attributed to the presence of antiphase domain boundaries. Following Cottrell's domain hardening mechanism, numerous workers have proposed other refined models also involving the presence of domain boundaries. Using the anomalous X-ray diffraction technique, Davies and Stoloff have shown that the hardness of the Ni3Fe superlattice varies with the domain size. So far, no direct observation of antiphase domain boundaries in Ni3Fe has been reported. Because the atomic scattering factors of the elements in NijFe are so close, the superlattice reflections are not easily detected. Furthermore, the domain configurations in NioFe are thought to be independent of the crystallographic orientations.

Raman And Fluorescence Spectra Observed in Laser Microprobe Measurements of Several Compositions in the Ln-Ba-Cu-O System

1990 ◽  
Vol 48 (2) ◽  
pp. 278-279
Author(s):  
Edgar S. Etz ◽  
Thomas D. Schroeder ◽  
Winnie Wong-Ng
Keyword(s):  
Fluorescence Spectra ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Ceramic Powders ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Raman Microprobe ◽  
Methods Of Synthesis ◽  
Compositional Homogeneity ◽  
Processing Techniques

We are investigating by Raman microprobe measurements the superconducting and related phases in the LnBa2Cu3O7-x (for x=0 to 1) system where yttrium has been replaced by several of the lanthanide (Ln = Nd,Sm,Eu,Ho,Er) elements. The aim is to relate the observed optical spectra (Raman and fluorescence) to the compositional and structural properties of these solids as part of comprehensive materials characterization. The results are correlated with the methods of synthesis, the processing techniques of these materials, and their superconducting properties. Of relevance is the substitutional chemistry of these isostructural systems, the differences in the spectra, and their microanalytical usefulness for the detection of impurity phases, and the assessment of compositional homogeneity. The Raman spectra of most of these compounds are well understood from accounts in the literature.The materials examined here are mostly ceramic powders prepared by conventional solid state reaction techniques. The bulk samples are of nominally single-phase composition as determined by x-ray diffraction.

Observation of pseudo 10-fold symmetry in the ordered iron-zinc delta phase

1992 ◽  
Vol 50 (1) ◽  
pp. 36-37
Author(s):  
L. A. Giannuzzi ◽  
A. S. Ramani ◽  
P. R. Howell ◽  
H. W. Pickering ◽  
W. R. Bitler
Keyword(s):  
Single Phase ◽  
X Ray Diffraction ◽  
Rich Region ◽  
Average Cell ◽  
X Ray ◽  
Delta Phase ◽  
Cell Dimensions ◽  
Δ Phase ◽  
Morphological Differences ◽  
Concentration Discontinuity

The δ phase is a Zn-rich intermetallic, having a composition range of ∼ 86.5 - 92.0 atomic percent Zn, and is stable up to 665°C. The stoichiometry of the δ phase has been reported as FeZn7 and FeZn10 The deviation in stoichiometry can be attributed to variations in alloy composition used by each investigator. The structure of the δ phase, as determined by powder x-ray diffraction, is hexagonal (P63mc or P63/mmc) with cell dimensions a = 1.28 nm, c = 5.76 nm, and 555±8 atoms per unit cell. Later work suggested that the layer produced by hot-dip galvanizing should be considered as two distinct phases which are characterized by their morphological differences, namely: the iron-rich region with a compact appearance (δk) and the zinc-rich region with a columnar or palisade microstructure (δp). The sub-division of the δ phase was also based on differences in diffusion behavior, and a concentration discontinuity across the δp/δk boundary. However, work utilizing Weisenberg photographs on δ single crystals reported that the variation in lattice parameters with composition was small and hence, structurally, the δk phase and the δp phase were the same and should be thought of as a single phase, δ. Bastin et al. determined the average cell dimensions to be a = 1.28 nm and c = 5.71 nm, and suggested that perhaps some kind of ordering process, which would not be observed by x-ray diffraction, may be responsible for the morphological differences within the δ phase.

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