Chalkogenides of the transition elements. VI. X-Ray, neutron, and magnetic investigation of the spinels Co3O4, NiCo2O4, Co3S4, and NiCo2S4

1968 ◽  
Vol 46 (22) ◽  
pp. 3463-3476 ◽  
Author(s):  
Osvald Knop ◽  
K. I. G. Reid ◽  
Sutarno ◽  
Yasuaki Nakagawa
Keyword(s):  
Neutron Diffraction ◽  
High Spin ◽  
Room Temperature ◽  
Spin States ◽  
Transition Elements ◽  
Thermal Stabilities ◽  
Magnetization Measurements ◽  
X Ray ◽  
Magnetic Investigation ◽  
Diffraction Patterns

The crystal structures of the spinels Co3O4, NiCo2O4, Co3S4, and NiCo2S4 were refined from X-ray and neutron powder data. Their lattice parameters at room temperature and the positional parameters of the oxygen and sulfur atoms were: Co3O4, 8.0835 ± 6 Å, 0.2640 ± 8; NiCo2O4, 8.114 ± 14 Å, 0.2583 ± 34; Co3S4, 9.4055 ± 12 Å, 0.2591 ± 5; NiCo2S4, 9.3872 ± 7 Å, 0.2591 ± 3. The thermal stabilities of the two oxides in air and in oxygen at 1 atm were investigated by thermogravimetric analysis and differential thermal analysis, and the magnetization of NiCo2O4 was measured down to 4.2 °K in fields up to 11.70 kOe. From neutron diffraction NiCo2O4. was found to be inverse, while NiCo2S4 was shown to be normal. The results of the magnetization measurements and the neutron-diffraction patterns at 111 and 393 °K were found to be equally consistent with the magnetic structure proposed for NiCo2O4 by Blasse, Co2+[Ni3+Co3+]O4 (Co2+ in a high-spin and Ni3+ andCo3+ in low-spin states), and with Co3+[Ni2+Co3+]O4 (Co3+ in 8(a) in a high-spin and Co3+ in 16(d) in a low-spin state). The sublattice magnetizations were not completely aligned even at 4.2 °K; the net magnetic moment derived from the magnetization measurements was only 1.25 μB, which is lower than the value of 2 μB expected from either model. At 111 °K the moments of the ions in the tetrahedral and octahedral sites were estimated to be 1.9 ± 0.2 and −0.5 ± 0.1 bohr magnetons respectively.

The Effect of Al on Phase Stability and Oxidation Behavior in Ternary Nb-Ti-Si Alloys

2014 ◽  
Vol 556-562 ◽  
pp. 310-313
Author(s):  
Yong Jun Jiang
Keyword(s):  
Room Temperature ◽  
Oxidation Behavior ◽  
Point Of View ◽  
Transition Elements ◽  
X Ray Diffraction ◽  
X Ray ◽  
Room Temperature Ductility ◽  
Oxidation Properties ◽  
Diffraction Patterns ◽  
And Control

In this paper, we report a significant improvement in mechanical and oxidation properties of near eutectic Nb–Si alloys by the addition of aluminum (Al) and control of microstructural length scale. Thus in order to develop new alloys, we have to choose proper alloying elements keeping all the above issues in mind. Among the non-transition elements such as Al, Ga, Ge, Sn, and Al is most attractive from the point of view of enhancing the oxidation resistance and room temperature ductility due to substitution of Si with metallic Al . Al forms oxides which are even more thermodynamically stable than Si and Nb based oxides. Al is also soluble in Nb to a greater degree in conjunction with other refractory elementsFig.1 The figure shows composite X-ray diffraction patterns of each sample exposed to air for one hour in a TGA furnace at above mention temperatures.

Structural study of chlorine pentafluoride in the condensed phases

1978 ◽  
Vol 56 (10) ◽  
pp. 1353-1357 ◽  
Author(s):  
M. Drifford ◽  
R. Rousson ◽  
J. M. Weulersse
Keyword(s):  
Raman Spectrum ◽  
Neutron Diffraction ◽  
Raman Spectra ◽  
Vibrational Spectra ◽  
Room Temperature ◽  
Condensed Phases ◽  
Body Centered Cubic ◽  
X Ray ◽  
Solid Phases ◽  
Diffraction Patterns

Raman spectra of chlorine pentafluoride have been investigated in the condensed phases between room temperature and 4 K. X-Ray and neutron diffraction patterns were also recorded. The three solid phases previously described by nmr measurements have been characterised. Solid 1(161 K < T < 181 K) is body-centered cubic with a = 5.7 Å; its Raman spectrum is quite comparable with that of the liquid. Solid II (117 K < T < 161 K) is orthorhombic with a = 6.17 Å, b = 7.22 Å; c = 7.66 Å; according to the Raman spectra its structure seems to be similar to that of solid BrF5. The structure of solid III (T < 117 K) has not been determined; however, the vibrational spectra show that it is not very different from solid II.The analogy between the structures of the tri- and pentafluorides of chlorine and bromine is discussed.

scholarly journals Chalkogenides of the Transition Elements. VIII. An X-Ray and Neutron Diffraction Study of the Spinel CoNi2S4

1971 ◽  
Vol 49 (4) ◽  
pp. 598-602 ◽  
Author(s):  
Chung-Hsi Huang ◽  
Osvald Knop
Keyword(s):  
Crystal Structure ◽  
Neutron Diffraction ◽  
Sulfur Atom ◽  
Room Temperature ◽  
Lattice Parameter ◽  
Neutron Diffraction Study ◽  
Transition Elements ◽  
Inverse Spinel ◽  
X Ray ◽  
Neutron Powder Diffractometer

The crystal structure of the spinel CoNi2S4 was refined from X-ray and neutron powder-diffractometer data. The lattice parameter at room temperature and the positional parameter of the sulfur atom were determined as 9.424(1) Å and 0.2591(3). The neutron intensities show clearly that CoNi2S4 is an inverse spinel, Ni[CoNi]S4.

Physical and Mechanical Properties of Cement Paste Were Used Partially with Fly Ash and Kaolin Waste

2017 ◽  
Vol 866 ◽  
pp. 199-203
Author(s):  
Chidchanok Chainej ◽  
Suparut Narksitipan ◽  
Nittaya Jaitanong
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Room Temperature ◽  
Physical And Mechanical Properties ◽  
Partial Replacement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lime Water ◽  
Diffraction Patterns ◽  
Iron Mold

The aims of this research were study the microstructures and mechanical properties for partial replacement of cement with Fly ash (FA) and kaolin waste (KW). Ordinary Portland cement were partially replaced with FA and KW in the range of 25-35% and 10-25% by weight of cement powder. The kaolin waste was ground for 180 minutes before using. The specimen was packing into an iron mold which sample size of 5×5×5 cm3. Then, the specimens were kept at room temperature for 24 hours and were moist cured in the incubation lime water bath at age of 3 days. After that the specimens were dry cured with plastic wrap at age of 3, 7, 14 and 28 days. After that the compounds were examined by x-ray diffraction patterns (XRD) and the microstructures were examined by scanning electron microscopy (SEM). The compressive strength was then investigated.

X-Ray Diffraction Study of Hep Metals. I. Line Broadening in Polycrystalline Cd Powder

1974 ◽  
Vol 29 (12) ◽  
pp. 1771-1777 ◽  
Author(s):  
N. C. Haider ◽  
S. H. Hunter
Keyword(s):  
Room Temperature ◽  
Small Deformation ◽  
Correction Factors ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
Fault Probability ◽  
Large Particle Size ◽  
X Ray ◽  
Melting Temperatures ◽  
Diffraction Patterns

Powder Cd of 99.999% purity was prepared at room temperature (25 °C) and x-ray diffraction patterns were obtained using CuKaα radiation with Ni-filter. The line broadening was analyzed after incorporating the appropriate correction factors. At room temperature Cd was found to have large particle size (653 A), small root mean square strain (.001), small deformation fault probability a (.003). and negligible growth fault probability β(0). Compared to other hep metals which have been studied earlier and which have higher melting temperatures, metal Cd is much less affected by mechanical deformation at room temperature.

CRYSTAL STRUCTURE OF ZIRCONIUM TRICHLORIDE

1964 ◽  
Vol 42 (10) ◽  
pp. 1886-1889 ◽  
Author(s):  
B. Swaroop ◽  
S. N. Flengas
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Main Cell ◽  
Diffraction Patterns

The crystal structure of zirconium trichloride was determined from X-ray diffraction patterns. Zirconium trichloride belongs to the [Formula: see text]space group. The dimensions of the main cell at room temperature are: a = 5.961 ± 0.005 Å and c = 9.669 ± 0.005 Å.The density of zirconium trichloride was measured and gave the value of 2.281 ± 0.075 g/cm3 while, from the X-ray calculations, the value was found to be 2.205 g/cm3.

Magnetoresistance and Structure of Granular Co/Ag Thin Films

1993 ◽  
Vol 313 ◽  
Author(s):  
Mary Beth Stearns ◽  
Yuanda Cheng
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Room Temperature ◽  
Magnetization Measurements ◽  
X Ray ◽  
Conduction Electrons ◽  
Low Field ◽  
Co Concentration ◽  
Microscopy Techniques ◽  
Substrate Temperatures

ABSTRACTSeveral series of CoxAg1-x granular thin films (-3000Å) were fabricated by coevapora-tion of Co and Ag in a dual e-beam UHV deposition system at varying substrate temperatures. These films have low field magnetoresistance values as large as 31% at room temperature and 65% at liquid N2 temperature. The structure of the films was determined using magnetization measurements as well as x-ray and various electron microscopy techniques. The composition was determined using Rutherford backscattering spectroscopy. The Magnetoresistance was measured at both room and liquid N2 temperatures.We deduce from the magnetization and RBS Measurements that the films consist of Co globules embedded in a Ag Matrix and that there is no appreciable mixing of the Co and Ag atoms in the films deposited at substrate temperatures ≥ 400°K. The size of the Co globules is seen to increase with increasing Co concentration and the maximum magnetoresistance occurs in those films having the smallest Ag thickness which provides magnetic isolation of the Co globules.We suggest that the large magnetoresistance of these films arises from the same mechanism which causes the low field magnetoresistance in pure ferromagnets, namely, the scattering of the highly polarized d conduction electrons of the Co at magnetic boundaries. The large increase in the room temperature magnetoresistance of the CO/Ag films as compared to those of pure 3d ferromagnetic films is due to the distance between the magnetic boundaries being reduced to a few nanometers, because of the small size of the single domain Co globules, as compared to a few microns in 3d ferromagnets.

scholarly journals Ferromagnetic Order in the Intermetallic Alloys laNi5-xMgx

2012 ◽  
Vol 29 (1) ◽  
pp. 50
Author(s):  
D.N Ba ◽  
L.T Tai ◽  
N.T Trung ◽  
N.T Huy
Keyword(s):  
Magnetic Properties ◽  
Curie Temperature ◽  
Room Temperature ◽  
Single Phase ◽  
Chemical Doping ◽  
Intermetallic Alloys ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ferromagnetic Order ◽  
Diffraction Patterns

The influences of the substitution of Ni with Mg on crystallographic and magnetic properties of the intermetallic alloys LaNi5-xMgx (x ≤ 0.4) were investigated. The X-ray diffraction patterns showed that all samples were of single phase, and the lattice parameters, a and c, decreased slightly upon chemical doping. LaNi5 is well known as an exchange-enhanced Pauli paramagnet. Interestingly, in LaNi5-xMgx, the ferromagnetic order existed even with a small amount of dopants; the Curie temperature reached the value of room temperature for x = 0.2, and enhanced with increasing x.

A Chemical Solution Route to Rapid Synthesis of Homogeneous Bi100−xSbx Alloys Nanoparticles at Room Temperature

2007 ◽  
Vol 7 (2) ◽  
pp. 525-529 ◽  
Author(s):  
Bo Zhou ◽  
Jun-Jie Zhu
Keyword(s):  
Room Temperature ◽  
Raw Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Solution Route ◽  
Diffraction Patterns ◽  
Co Reduction ◽  
Chemical Solution Route

A chemical co-reduction route in aqueous solution was developed to synthesize Bi100−xSbx alloys at room temperature. The hydrolyses of Bi(III) and Sb(III) were effectively avoided by selecting proper raw materials and coordinator. X-ray diffraction analysis indicated that the as-prepared Bi100−xSbx alloys were homogeneous and phase-pure, and the Bi/Sb ratios in the alloys were very close to those in the aqueous solutions. The transmission electron microscope observation showed that the as-prepared Bi100−xSbx (x = 0∼100) alloys were particles with a size of tens of nanometers. The selected area electron diffraction patterns confirmed the high crystallinity, the homogeneousness, and the composition controllability of as-prepared alloys. All these characters and the nanometer-scaled size of the alloys are believed to be beneficial to the thermoelectric property of the Bi100−xSbx alloys.

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