X-ray diffraction studies on La1.85Sr0.15CuO4 doped with Mg in high doping level

1997 ◽  
Vol 282-287 ◽  
pp. 787-788 ◽  
Author(s):  
X.S. Wu ◽  
Z.Q. Mao ◽  
J. Lin ◽  
W.M. Chen ◽  
X. Jin ◽  
...  
Keyword(s):  
Doping Level ◽  
X Ray Diffraction ◽  
High Doping Level ◽  
X Ray

The Effect of IrO2 Doping on the Structure and Magnetic and Magnetotransport Properties of La0.7Ca0.2Sr0.1MnO3 Composite

2010 ◽  
Vol 150-151 ◽  
pp. 774-778 ◽  
Author(s):  
Fen Fen Wei ◽  
Cao Shui Xiong ◽  
Ke Jin Gou ◽  
Hui Liao ◽  
Juan Hou
Keyword(s):  
Doping Level ◽  
Room Temperature ◽  
Solid State Reaction Method ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
High Doping Level ◽  
X Ray ◽  
Double Peaks ◽  
Curie Temperature Tc ◽  
Perovskite Lattice

La0.7Ca0.2Sr0.1MnO3/xIrO2 (LCSMO/xIrO2) compounds were fabricated by solid state reaction method. X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and Dc four probed method were used to investigate the structure, magnetic and magnetotransport properties. The results show that at low doping level (x≤0.15) IrO2 goes into the perovskite lattice substituting Mn in LCSMO, but at high doping level (x≥0.20) some part of the IrO2 substituted for Mn4+ in LCSMO lattice and the remainder resided in the grain boundaries in the form of IrO2. LCSMO/xIrO2 composites are influenced remarkabled by the IrO2 doping. With increasing IrO2 addition, the magnetic moment (s) decreases and Curie temperature (TC) decreases first, and then rises slowly of the compounds; In the doping range of 0~0.35, the resistivity rises first, and then decreases slowly, furthermore, the resistivity versus appears double peaks with increasing IrO2 addition. At room temperature, the magnetoresistance (MR) of the composites have been improved remarkably.

A Structural Investigation of Polypyrrole as a Function of Oxidation State

2005 ◽  
Vol 871 ◽  
Author(s):  
Mya R. Warren ◽  
John D. Madden
Keyword(s):  
Oxidation State ◽  
Polymer Matrix ◽  
Doping Level ◽  
Structural Changes ◽  
Structural Investigation ◽  
One Dimension ◽  
X Ray Diffraction ◽  
Linear Contraction ◽  
X Ray ◽  
Sudden Contraction

AbstractPolypyrrole exhibits actuation under electrochemical doping and undoping of the polymer matrix. Active strain and x-ray diffraction measurements are performed in order to correlate the microscopic and macroscopic structural changes occurring during actuation. Under galvanostatic reduction, the film shows first a linear contraction with oxidation state due to expulsion of small anions. At 50% of the as-grown doping level, the film reverses direction and begins to expand, possibly due to incorporation of the larger cations. X-ray diffraction, however, does not show a linear contraction or expansion in the crystalline portions of the polymer. The polymer crystallites go through a sudden contraction in one dimension of approximately 14%, and otherwise remain constant. The contraction in the polypyrrole crystals occurs at the 50% doping level, and may be correlated with the reversal of macroscopic actuation.

Magnetic Property of Hole-Doped Double Perovskite Compound

2013 ◽  
Vol 464 ◽  
pp. 50-53
Author(s):  
Suo Jia Yuan ◽  
Qin Zhang ◽  
Hai Bo Sun ◽  
Hui Wang
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Doping Level ◽  
Single Phase ◽  
Magnetic Measurements ◽  
Double Perovskite ◽  
Cation Ordering ◽  
High Doping Level ◽  
Xrd Pattern ◽  
X Ray

Crystal structure and magnetic properties of hole-doped double perovskite compounds (Sr, Na)2FeMoO6 have been investigated by means of X-ray powder diffraction (XRD) and magnetic measurements. XRD pattern indicates that all the samples are of single phase and belong to the space group I4/m. The degree of cation ordering in the Na-doped Sr2FeMoO6 compounds shows a non-monotonic variation with the doping level, increasing from x=0 to x=0.03 and decreasing slightly with further increase of the doping. However, the Curie temperature of the compound decreases at low doping level and increases at high doping level.

Antimony-Doped SnO2 Nanoparticles with Controlled Doping Level via Nonaqueous Sol-Gel Procedure

2013 ◽  
Vol 745-746 ◽  
pp. 685-689
Author(s):  
Jun Yan Wu ◽  
Fei Chen ◽  
Qiang Shen ◽  
Lian Meng Zhang
Keyword(s):  
Citric Acid ◽  
Photoelectron Spectroscopy ◽  
Doping Level ◽  
Sol Gel ◽  
Processing Parameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Adsorption Desorption ◽  
Controlled Doping

Antimony-doped tin oxide (ATO) nanoparticles with controlled doping level were prepared by a nonaqueous solution route, using alcohol as the solvent, citric acid as an agent, tin (IV) tetrachloride as tin source and antimony (III) chlorideas as antimony sources. As-synthesized samples were characterized by Thermogravimetric analysis (TGA), powder X-ray diffraction (XRD), transmission electron micrographs (TEM), N2 adsorption-desorption isotherms, and X-ray photoelectron spectroscopy (XPS). The results showed that the content of citric acid was the most important processing parameter which was largely governing the reaction course and the complete incorporation of Sb. When the citric acid to metal mol ratio was 2, the particles were the highly crystallized ATO nanoparticles of about 20nm and the Sb atoms were indeed incorporated into the SnO2 crystal structure (cassiterite SnO2).

The anisotropic powder metallurgy of n-type Bi2Te2.85Se0.15 thermoelectric material

1990 ◽  
Vol 5 (5) ◽  
pp. 1052-1057 ◽  
Author(s):  
Hideo Wada ◽  
Tetuji Sato ◽  
Kazuaki Takahashi ◽  
Norio Nakastukasa
Keyword(s):  
Particle Size ◽  
Powder Metallurgy ◽  
Thermoelectric Properties ◽  
Thermoelectric Material ◽  
Hot Pressing ◽  
Doping Level ◽  
Orientation Factor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermoelectric Measurements

The anisotropic powder metallurgy of n-type Bi2Te2.85Se0.15 doped with bromines was studied by both x-ray diffraction and thermoelectric measurements. The statistical orientation of platelet-like grains in the samples was characterized using the orientation factor estimated by the Lotgering formula from (0,0,1) x-ray diffraction intensities. It is demonstrated that the orientation factor which is strongly influenced by the hot-pressing conditions and the particle size of the starting material has a strong effect on the thermoelectric properties of the samples in this system. This implies that the powder metallurgy has the additional freedom of controlling the thermoelectric properties in addition to the doping level in the grains.

Influence of oxygen impurity on containerless solidification of quasicrystalline-forming Zr80Pt20 alloy

2013 ◽  
Vol 1528 ◽  
Author(s):  
Takeshi Harada ◽  
Akitoshi Mizuno ◽  
Masahito Watanabe
Keyword(s):  
Oxygen Content ◽  
Doping Level ◽  
Metastable Phase ◽  
Primary Phase ◽  
Oxygen Impurity ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Metastable Phase Formation ◽  
Containerless Solidification

ABSTRACTThe influence of oxygen content on containerless solidification of Zr80Pt20 alloy has been studied by using conical nozzle levitation (CNL) technique. The doping level of oxygen from 41 to 5450 ppm mass oxygen (PMO) affects the undercooling of the liquid Zr80Pt20 alloy. Time-resolved synchrotron x-ray diffraction revealed that the quasicrystalline (QC) phase precipitated as a primary phase during solidification of the Zr80Pt20 alloy. The amount of the QC phase depends on the oxygen content in the alloy. This indicates that the doping level of oxygen in Zr80Pt20 alloy can be related to the metastable phase formation as well as the glass-formation ability.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Ribosome Structural Organization

1974 ◽  
Vol 32 ◽  
pp. 332-333
Author(s):  
James A. Lake
Keyword(s):  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Small Subunit ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Specific Antibodies ◽  
X Ray ◽  
E Coli ◽  
Complete Sequences

The understanding of ribosome structure has advanced considerably in the last several years. Biochemists have characterized the constituent proteins and rRNA's of ribosomes. Complete sequences have been determined for some ribosomal proteins and specific antibodies have been prepared against all E. coli small subunit proteins. In addition, a number of naturally occuring systems of three dimensional ribosome crystals which are suitable for structural studies have been observed in eukaryotes. Although the crystals are, in general, too small for X-ray diffraction, their size is ideal for electron microscopy.

Electron Microscopy of Human Gallstones

1971 ◽  
Vol 29 ◽  
pp. 296-297
Author(s):  
C. Wolpers ◽  
R. Blaschke
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Bile Pigment ◽  
X Ray Diffraction ◽  
Triclinic Crystal System ◽  
X Ray ◽  
Follow Up Study ◽  
Infra Red ◽  
Main Components

Scanning microscopy was used to study the surface of human gallstones and the surface of fractures. The specimens were obtained by operation, washed with water, dried at room temperature and shadowcasted with carbon and aluminum. Most of the specimens belong to patients from a series of X-ray follow-up study, examined during the last twenty years. So it was possible to evaluate approximately the age of these gallstones and to get information on the intensity of growing and solving.Cholesterol, a group of bile pigment substances and different salts of calcium, are the main components of human gallstones. By X-ray diffraction technique, infra-red spectroscopy and by chemical analysis it was demonstrated that all three components can be found in any gallstone. In the presence of water cholesterol crystallizes in pane-like plates of the triclinic crystal system.

High Resolution Replication of Organoclay Surfaces

1982 ◽  
Vol 40 ◽  
pp. 576-577
Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys
Keyword(s):  
Clay Mineral ◽  
Organic Molecule ◽  
Organic Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Naturally Occurring ◽  
Silicate Layers ◽  
Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

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