Identification of Several New Ferromagnetic and Antiferromagnetic Rare Earth Cuprates

1990 ◽  
Vol 48 (2) ◽  
pp. 498-499
Author(s):  
M. Fendorf ◽  
S.W. Keller ◽  
A.M. Stacy ◽  
R. Gronsky
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Rare Earth ◽  
Magnetic Behavior ◽  
Chemical Form ◽  
The Other ◽  
X Ray ◽  
Scanning Electron ◽  
The Eu

Several new rare earth cuprates having the chemical form RxCuyOz (where R represents the rare earths La, Nd, Sm, Eu, and Gd) have recently been synthesized using a NaOH flux at 400°C. The materials are polycrystalline, and contain varying amounts of R2CuO4 and CuO. During subsequent susceptibility measurements using a SQUID magnetometer, it was found that the Gd material orders antiferromagnetically at approximately 14K, while the other compounds become ferromagnetic between 18K and 28K. Treatment of the powders with 12M HC1 for several minutes dissolves the impurity R2CuO4 and CuO phases, thus facilitating efforts to determine the composition and crystal structure of the new ferromagnetic and antiferromagnetic cuprates. Details of synthesis and magnetic behavior of these materials are to be published elsewhere. In this study, a first attempt is made to characterize the Eu and Gd materials.Energy dispersive x-ray analysis carried out during scanning electron microscopy work indicates that the R:Cu ratio in the Gd material is 1:1.70 (close to 3:5) and that in the Eu material is 1:1.96 (close to 1:2).

SYNTHESIS, MORPHOLOGY AND STRUCTURAL PROPERTIES OF (GD,ND)SR2RUCU2O8 SAMPLES

2003 ◽  
Vol 17 (04n06) ◽  
pp. 899-904 ◽  
Author(s):  
A. VECCHIONE ◽  
M. GOMBOS ◽  
C. TEDESCO ◽  
A. IMMIRZI ◽  
L. MARCHESE ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Solid State ◽  
Powder Diffraction ◽  
Solid State Reaction ◽  
X Ray ◽  
Structure And Morphology ◽  
Polycrystalline Powder ◽  
Scanning Electron

NdSr 2 RuCu 2 O x material has been prepared as polycrystalline powder by solid state reaction. The compound has been investigated by synchrotron x-ray powder diffraction and scanning electron microscopy. The experimental results show that the average crystal structure is a disordered cubic perovskite with Nd and Sr cations occupying the same site and the same substitution is found for Cu and Ru atoms. A comparison between the crystal structure and morphology of this compound and the superconducting tetragonal GdSr 2 RuCu 2 O 8 is also discussed.

scholarly journals Standard Hot Pressing as a Possible Solution to Obtain Dense K0.5Na0.5NbO3 Ceramic Doped by Er2O3 and Yb2O3

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4171 ◽  
Author(s):  
Paweł Rutkowski ◽  
Jan Huebner ◽  
Adrian Graboś ◽  
Dariusz Kata ◽  
Dariusz Grzybek ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Rare Earth ◽  
Phase Composition ◽  
Powder Mixture ◽  
Hot Pressing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ultrasonic Methods ◽  
Scanning Electron

In this study, the influence of the addition of rare earth oxides on the phase composition and density of KNN piezoelectric ceramics was investigated. The initial powders of Na2CO3 and K2CO3 were dried at 150 °C for 2 h. Then, a powder mixture for synthesis was prepared by adding a stoichiometric amount of Nb2O5 and 5 and 10 wt % overabundance of Na2CO3. All powders were mixed by ball-milling for 24 h and synthesized at 950 °C. The phase composition of the reaction bed was checked by means of X-ray diffraction (XRD). It had an appearance of tetragonal and monoclinic K0.5Na0.5NbO3 (KNN) phases. Then, 1 and 2 wt % of Er2O3 and Yb2O3, were added to the mixture. Green samples of 25 mm diameter and 3 mm thickness were prepared and sintered by hot pressing at 1000 °C for 2 h under 25 MPa pressure. The final samples were investigated via scanning electron microscopy (SEM)-energy-dispersive X-ray spectroscopy (EDS), XRD, Rietveld, and ultrasonic methods. Phase analysis showed tetragonal and orthorhombic KNN phases, and a contamination of (K2CO3·1.5H2O) was present. The obtained KNN polycrystals had a relative density above 95%. Texturing of the material was confirmed as a result of hot pressing.

Study on Microstructure of NiCrMoY Alloy Coatings

2014 ◽  
Vol 577 ◽  
pp. 62-65
Author(s):  
Chun Lian Hu ◽  
Shang Lin Hou
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Rare Earth ◽  
High Frequency ◽  
Flame Spray ◽  
X Ray Diffraction ◽  
X Ray ◽  
New Phase ◽  
Scanning Electron ◽  
High Frequency Induction

The microstructure of rare earth NiCrMoY alloy manufactured by atomization and oxygen-acetylene flame spray and high frequency induction remelting technique is investigated by a combination of scanning electron microscopy (SEM), energy spectrum, X-ray diffraction meter (XRD). The results indicate that Microstructure of NiCrMoY alloy coatings are finer and bulk-and needle-like hard Metallograph are precipitated, a new phase MoB is produced.

Crystal Structure of BiFeO3 Synthesized Using the Hydrothermal Processing

2014 ◽  
Vol 602-603 ◽  
pp. 947-950
Author(s):  
Zhen Wang ◽  
Hai Yan Chen ◽  
Lin Qiang Gao ◽  
Xin Zou
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Single Phase ◽  
Hydrothermal Processing ◽  
Optimal Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

BiFeO3 nanoparticles were successfully synthesized by a hydrothermal method by a mineralizer (KNO3). Structural characterization was performed by thermal analysis, powder X-ray diffraction (XRD) and scanning electron microscopy (TEM).The results showed that the products were perovskite structure BiFeO3 powders. Optimal conditions for the synthesis of single-phase BiFeO3 ceramics were obtained.

scholarly journals Synthesis, Crystal Structure Refinement, and Electrical Conductivity of Pb(8−x)Na2Smx(VO4)6O(x/2)

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Tatiana M. Savankova ◽  
Lev G. Akselrud ◽  
Lyudmyla I. Ardanova ◽  
Alexey V. Ignatov ◽  
Eugeni I. Get’man ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Scanning Electron Microscopy ◽  
Solid Solutions ◽  
Structure Refinement ◽  
Crystal Structure Refinement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Solid solutions of Pb(8−x)Na2Smx(VO4)6O(x/2)were studied using X-ray diffraction analysis including Rietveld refinement and scanning electron microscopy and by measuring their electrical conductivity. Crystal structure of the solid solutions was refined and the solubility region0≤x≤0.2was determined for samarium substitution for lead under the scheme2Pb2++□→2Sm3++O2-. The influence of degree of substitution on the electrical conductivity of solid solutions was established.

scholarly journals Synthesis of Zeolite A employing Amazon kaolin waste

Cerâmica ◽  
2015 ◽  
Vol 61 (360) ◽  
pp. 409-413 ◽  
Author(s):  
S. H. da Silva Filho ◽  
L. Bieseki ◽  
A. R. da Silva ◽  
A. A. B. Maia ◽  
R. A. S. San Gil ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Amorphous Materials ◽  
Mas Nmr ◽  
The Other ◽  
Zeolite A ◽  
X Ray Diffraction ◽  
X Ray ◽  
27Al Mas Nmr ◽  
Scanning Electron

Abstract The synthesis of zeolite A employing kaolin waste from paper coating was studied. The kaolin waste was pre-treated at 550 to 800 ºC. For comparison purposes, a sample of zeolite A was also prepared using the IZA procedure. The materials were characterized by 27Al MAS NMR, X-ray diffraction and scanning electron microscopy using a microprobe. Pretreatment was necessary, and the best temperatures were between 600 and 700 ºC. The zeolite A formation was observed in all the prepared materials, reaching 52% crystallinity. On the other hand, the sodalite phase and amorphous materials were also formed.

Template-Free Synthesis of α-Fe2O3 Hollow Spheres and Nanocubes

2011 ◽  
Vol 361-363 ◽  
pp. 2012-2015
Author(s):  
Chang Yun Chen ◽  
Feng Zhou ◽  
Chun Hua ◽  
Zhao Hui Li ◽  
Huan Pang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hollow Spheres ◽  
Magnetic Characteristic ◽  
The Other ◽  
X Ray Diffraction ◽  
Facile Hydrothermal Method ◽  
X Ray ◽  
Template Free ◽  
Scanning Electron

A facile hydrothermal method without any templates has been developed for the preparation of α- Fe2O3nanocubes and hollow spheres. The as-synthesized products is then characterized using X-ray diffraction(XRD), scanning electron microscopy(SEM). The nanocubes have extraordinary unity and we can anticipate its unique magnetic characteristic. On the other hand, the hollow sphere structure has a promising future in the application as carriers for targeting drug delivery. In our opinions, the method is not only very simple, but also is very friendly to the environment.

Effects of Rare Earth on Microstructure and Mechanical Properties of Al-3.2Mg Alloy

2015 ◽  
Vol 817 ◽  
pp. 192-197
Author(s):  
Xin Zhang ◽  
Ze Hua Wang ◽  
Ze Hua Zhou ◽  
Jian Ming Xu ◽  
Zhao Jun Zhong ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Grain Size ◽  
Tensile Strength ◽  
Rare Earth ◽  
Second Phase ◽  
Phase Precipitation ◽  
X Ray ◽  
Scanning Electron

A series of Al-3.2Mg alloys with addition of 0~1.6 wt.% rare earth (Ce and La) were prepared. The microstructure of as-cast Al-3.2Mg alloys was investigated by optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and the tensile strength was measured. The results indicated that the addition of rare earth elements refined grain size and secondary dendrite arm spacing (SDAS), and the tensile strength was affected by means of the second-phase precipitation and the grain boundary. Accordingly, the ductility of Al-3.2Mg alloys reduced with the increasing of RE addition due to the more second-phase formation.

The Effect of the Distribution of Ag in High TC Bi- Compound Superconductors

1989 ◽  
Vol 169 ◽  
Author(s):  
Alexis S. Nash ◽  
K. C. Goretta ◽  
Philip Nash ◽  
R. B. Poeppel ◽  
Donglu Shi
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Solid State ◽  
Energy Dispersive Spectrometry ◽  
Temperature Data ◽  
Energy Dispersive ◽  
High Tc ◽  
X Ray ◽  
Scanning Electron

AbstractA series of 4336 Bi‐Sr‐Ca‐Cu oxide samples doped with 1 to 5% metallic Ag was prepared by solid state reaction. The distribution of Ag, the microstructure and the crystal structure of the samples were studied using energy dispersive spectrometry, EDS, scanning electron microscopy, SEM, and x‐ray diffractometry, XRD. Addition of Ag leads to a marked increase in preferred orientation with (001) planes perpendicular to the pressing direction in sintered pellets. The resistivity‐temperature data show an enhanced Tc in Ag‐doped samples under certain conditions. Energy dispersive spectrometry indicates that the dopant mostly segregates to the grain boundaries.

Behavior of Some Tungsten Carbide Coatings in Molten Zinc

1996 ◽  
Author(s):  
A.J. Stavros
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Tungsten Carbide ◽  
The Other ◽  
Time To Failure ◽  
X Ray Diffraction ◽  
Molten Zinc ◽  
X Ray ◽  
Carbide Coatings ◽  
Scanning Electron

Abstract Two different W-Co-C powders were used in three deposition devices, the Super D-Gun, Jet Kote, and JP-5000 to produce coatings for laboratory immersion tests in molten zinc and %55Al-Zn. Resistance was evaluated as time to failure. Scanning electron microscopy and X-ray diffraction were used to characterize the structures ssid failure mechanism. All coatings were found to fail when the molten metal breached the coating thickness at weak spots and spread out over the underlying interface to lift the coating away from the underlying 316L substrate. These weak spots were "pits" on one Super D-Gun coating (the most resistant coating) and cracks on all the other coatings. No diffusion of zinc through the tungsten carbide coatings was observed.

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