Local Order Refinement in Liquid Lithium Niobate Using a Two Radiation Method (X-Rays and Neutrons)

1993 ◽  
Vol 48 (10) ◽  
pp. 955-964 ◽  
Author(s):  
P. Andonov ◽  
P. Chieux ◽  
S. Kimura ◽  
Y. Waseda
Keyword(s):  
Lithium Niobate ◽  
Pair Correlation ◽  
High Accuracy ◽  
Liquid Lithium ◽  
Local Order ◽  
X Rays ◽  
X Ray ◽  
Coordination Numbers ◽  
Structure Factors ◽  
Total Structure

Abstract In the molten LiNbO3 , the local order of the first neighbouring atoms has been described using the total structure factors S(Q) (x) and S(Q)(n) and the total pair correlation functions G(r) (x) and G(r)(n) obtained by X-ray and neutron scattering, respectively. We have also compared the differences [RDF(r)(x) - RDF(r)(n)] of the radial distributions obtained from experiments and computed from the distances in the LiNbO3 crystal. With this refinement it was possible to extract the first pair distances r 1,Nb-o r1, Li-O an r1,O-O whit the high accuracy Δr/r ≈ 0.5%. These values are identical with those in the crystal. Fitting the RDF curves by Gaussian components centred around these distances, the first coordination numbers n 1,Nb-o n1, Li-O and n1,O-O , have been determined with an accuracy Δn/n ≈ 2%. Octahedrally coordinated niobium atoms are present in the melt in the studied range from 1623 K to 1490 K. From these results it is inferred that aggregates built from corner-sharing octahedra, tightened by lithium atoms, are present in the melt.

X-Ray Diffraction Study on the Structure of the Metallic Glasses Mg84Ni16 and Mg30Ca70

1983 ◽  
Vol 38 (11) ◽  
pp. 1206-1209 ◽  
Author(s):  
E. Nassif ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Metallic Glasses ◽  
Pair Correlation ◽  
Structural Features ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coordination Numbers ◽  
Structure Factors ◽  
Short Range Ordering ◽  
Gaussian Fit ◽  
Total Structure

The total structure factors as well as the total pair correlation functions of amorphous Mg84Ni16 and Mg30Ca70 were determined by X-ray diffraction. The Mg-Ni glass shows rather strong chemical short range ordering. By Gaussian fit of the total pair correlation function partial coordination numbers and atomic distances were obtained. Similar surrounding of the Ni atoms in the amorphous phase and in crystalline Mg2Ni was found. The structural features of the Mg-Ca glass differ from those of the Mg-Ni glass

Structure of Mn-Si-Melts by Means of X-Ray Diffraction

1983 ◽  
Vol 38 (10) ◽  
pp. 1093-1097 ◽  
Author(s):  
E. Nassif ◽  
P. Lamparter ◽  
B. Sedelmeyer ◽  
S. Steeb
Keyword(s):  
Structure Factor ◽  
Melt Spinning ◽  
Pair Correlation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coordination Numbers ◽  
Glass Forming ◽  
Structure Factors ◽  
Total Structure Factor ◽  
Total Structure

Abstract The binary molten alloys Mn74Si26 and Mn33.5Si66.5 have been investigated by means of X-ray diffraction. The total structure factors as well as the total pair correlation functions were evaluated. The interatomic distances and total coordination numbers are given. The structural results for Mn74Si26 were compared to those for amorphous Mn74Si23P3 and for a tetrahedral packing model. A pronounced shoulder on the second maximum of the structure factor, which normally is characteristic for the curves obtained with amorphous substances was observed for the Mn74Si26 melt. With the Mn33.5Si66.5 melt, however, this feature cold not be observed. Since with this concentration no glass forming by melt spinning is possible, a correlation between the shape of the second maximum of a total structure factor and the glass forming ability of the corresponding melt is suggested.

scholarly journals X-Ray and Neutron Diffraction of Amorphous Nickel-Zirconium-Alloys as Prepared in Different Ways

1991 ◽  
Vol 46 (6) ◽  
pp. 491-498 ◽  
Author(s):  
L. Schultz ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Neutron Diffraction ◽  
Short Range ◽  
Melt Spinning ◽  
Short Range Order ◽  
Pair Correlation ◽  
Zirconium Alloys ◽  
X Ray ◽  
Coordination Numbers ◽  
Structure Factors ◽  
The One

AbstractThe structure of amorphous NiχZr100-χ-alloys (Χ= 30, 31, 34, 63.7, and 65), which were produced by melt spinning (MS), mechanical alloying (MA), and sputtering (SP) was studied by X-ray- and neutron diffraction yielding structure factors, pair correlation functions, coordination numbers, atomic distances, and Warren-Cowley chemical short range order parameters. The atomic arrangement within the first coordination sphere is independent of the method of preparation while in the second and higher spheres it differs between the MS- and the MA-alloys on the one side and the SP-specimens on the other side. Thus one understands that some physical properties of the different specimens differ

X-ray Diffraction Study of Amorphous NixZr(100-x)-Alloys Prepared by Melt-Spinning

1991 ◽  
Vol 46 (11) ◽  
pp. 947-950
Author(s):  
W.-M. Kuschke ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Melt Spinning ◽  
Pair Correlation ◽  
Nickel Concentration ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coordination Numbers ◽  
Structure Factors ◽  
Wide Range ◽  
Good Agreement

AbstractAmorphous Ni-Zr-alloys can be prepared by melt-spinning within a wide range of composition. Studies by X-ray diffraction yielded structure factors, pair correlation functions, total coordination numbers and atomic distances in dependence on the nickel concentration in the range of 25 up to 45 atomic percent. The change of the total coordination number and atomic distances turned out to be linear with the composition in this range. This is in good agreement with the linear composition dependence of the superconducting transition temperature, magnetic susceptibility, crystallization temperature, and electrical resistivity in the investigated range of composition.

Structural Investigation of the Metallic Glasses Mg85.5Cu14.5 and Mg70Zn30

1983 ◽  
Vol 38 (2) ◽  
pp. 142-148 ◽  
Author(s):  
E. Nassif ◽  
P. Lamparter ◽  
W. Sperl ◽  
S. Steeb
Keyword(s):  
Short Range ◽  
Short Range Order ◽  
Pair Correlation ◽  
Range Order ◽  
Order Effects ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Factors ◽  
Similar Chemical ◽  
Total Structure

Abstract The total structure factors as well as the total pair correlation functions for amorphous Mg85.5Cu14.5 (by neutron and X-ray diffraction) and for amorphous Mg70Zn30 (by X-ray diffraction) were determined. Both alloys show similar chemical short range order effects. From the total pair correlation function of the Mg85.5Cu14.5 glass, partial coordination numbers and atomic distances could be extracted. Comparison with the structure of crystalline Mg2Cu suggests that the short range order around the copper atoms is similar in the amorphous and the crystalline phase. The densities of both amorphous alloys were measured yielding negative excess volumina.

X-Ray Diffraction with Molten AuxMn100-x-Alloys

1995 ◽  
Vol 50 (9) ◽  
pp. 831-836
Author(s):  
R. M. Hagenmayer ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Correlation Functions ◽  
Short Range ◽  
Short Range Order ◽  
Pair Correlation ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Pair Correlation Functions ◽  
X Ray ◽  
Structure Factors ◽  
Total Structure

Abstract The molten alloys Au28.5Mn71.5 and Au68Mn32 are investigated with the energy dispersive X-ray diffraction method which works rather fast so that the evaporation loss of Mn from the molten alloys is kept low. From the observed prepeak follows that both melts are compound-forming but the gold rich melt Au68Mn32 shows only 50% of the short range order existent within the Au28.5Mn71.5 melt. Total structure factors and total pair correlation functions are discussed.

Structure of Molten Bi-Zn-Alloys by Means of Neutron Diffraction

1983 ◽  
Vol 38 (4) ◽  
pp. 395-398 ◽  
Author(s):  
W. Knoll ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Neutron Diffraction ◽  
Concentration Dependence ◽  
Correlation Functions ◽  
Pair Correlation ◽  
Nearest Neighbour ◽  
Pair Correlation Functions ◽  
Coordination Numbers ◽  
Structure Factors ◽  
Total Structure ◽  
Zn Alloys

Neutron diffraction experiments were performed with five molten Bi-Zn-alloys and the two molten elements Bi and Zn. The total structure factors and the pair correlation functions are given. The concentration dependence of the experimental nearest neighbour distances and the experimental coordination numbers is in accordance with the segregation behaviour prevailing in these melts.

ChemInform Abstract: Local Order Refinement in Liquid Lithium Niobate Using a Two Radiation Method (X-Rays and Neutrons).

ChemInform ◽  
2010 ◽  
Vol 25 (3) ◽  
pp. no-no
Author(s):  
P. ANDONOV ◽  
P. CHIEUX ◽  
S. KIMURA ◽  
Y. WASEDA
Keyword(s):  
Lithium Niobate ◽  
Liquid Lithium ◽  
Local Order ◽  
X Rays ◽  
Radiation Method

Structure of Sputtered Amorphous Zr-Hf-Si Alloys

1999 ◽  
Vol 54 (12) ◽  
pp. 699-703
Author(s):  
A. Pojtinger ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Amorphous Alloys ◽  
Short Range ◽  
Pair Correlation ◽  
Isomorphous Substitution ◽  
X Ray Diffraction ◽  
Partial Functions ◽  
X Ray ◽  
Structure Factors ◽  
Reverse Monte Carlo Simulation ◽  
Total Structure

Abstract Amorphous (Zr,Hf)37Si63 alloys were produced by sputtering. Their total structure factors were determined by X-ray diffraction. Using the methods of isomorphous substitution and Reverse Monte Carlo simulation, the partial pair correlation functions were obtained. The results were compared with the partial functions of amorphous Ti40Si60. In the amorphous alloys under investigation the transition metal -metalloid correlation dominates the short range order.

Atomic Structure of Rare Earth Si-Al-O-N Glasses

1998 ◽  
Vol 53 (5) ◽  
pp. 259-264 ◽  
Author(s):  
H. Uhlig ◽  
M.-J. Hoffmann ◽  
S. Steeb
Keyword(s):  
Rare Earth ◽  
Neutron Diffraction ◽  
Atomic Structure ◽  
Pair Correlation ◽  
X Ray Diffraction ◽  
Ionic Radii ◽  
X Ray ◽  
Structure Factors ◽  
Total Structure

Abstract In this paper the results of X-ray diffraction experiments of Ln-Si-Al-O-N (Ln = La, Gd, Yb) glasses are presented. Total structure factors and pair correlation functions allow the determination of the first coordination sphere of Ln atoms. The bond lengths observed correspond to the ionic radii of the Ln-ions surrounded by oxygen and nitrogen atoms. The presence of non-bridging nitrogen is discussed together with results of neutron diffraction, NMR-experiments and XPS-studies of other authors.

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