Structure Investigations on Se1-xTex Melts by Neutron Scattering and X-ray Diffraction

1981 ◽  
Vol 36 (8) ◽  
pp. 880-885 ◽  
Author(s):  
W. Hoyer ◽  
B. Kunsch ◽  
M. Suda ◽  
E. Wieser

Abstract Neutron scattering results on Se1-xTex melts (x = 0.3, 0.6, 0.8) obtained at 460 °C are combined with earlier X-ray diffraction data. The behaviour of the number and distance of nearest neighbours is discussed with respect to chemical short-range order and transition from twofold to three-fold coordination. For Se70Te30 the radial concentration correlation function 4πr2 ρcc(r) has been evaluated. It shows clearly the preferred formation of unlike pairs (Se-Te) within the chains.

1987 ◽  
Vol 42 (5) ◽  
pp. 507-510 ◽  
Author(s):  
E. Bühler ◽  
P. Lamparter ◽  
S. Steeb

By means of X-ray diffraction in transmission the molten MgxZn(1oo-x)-alloys (x = 0, 8, 15, 30, 40, 50, 60, 70, 73, 80, 90, 100) were investigated and the total structure factor S (Q) , the total pair correlation function, the number of nearest neighbours as well as the atomic distances were evaluated. For 30 ≦ x ≦ 80 a premaximum in S (Q) was observed which is caused by chemical short range order. The comparison of the premaximum of the Mg70Zn30-melt with that of the corresponding amorphous alloy shows that within the melt the chemical short range order amounts to about 40% of that of the amorphous alloy.


1975 ◽  
Vol 30 (2) ◽  
pp. 235-241 ◽  
Author(s):  
W. Hoyer ◽  
E. Thomas ◽  
M. Wobst

Abstract X-ray Diffraction Study of Molten Tellurium An X-ray diffraction apparatus with focusing geometry used for the investigation of free surfaces of melts and a computer programme for the analysis of scattering intensities are discribed. The results of our measurements on molten tellurium at 480, 550 and 620 °C are presented and compared with a model of the temperature change of the short range order in molten tellurium as described by Cabane, Tourand and Breuil 14-17. The important result is that the number of nearest neighbours is approximately 3 at all the 3 temperatures. This suggests that the short range order is changing at the melting point from a chain structure to an antimony-like structure.


Author(s):  
Dirk Holland-Moritz ◽  
Oliver Heinen ◽  
Robert Bellissent ◽  
Thomas Schenk ◽  
Dieter M. Herlach

1998 ◽  
Vol 05 (02) ◽  
pp. 459-464 ◽  
Author(s):  
L. D. Marks ◽  
D. Grozea ◽  
R. Feidenhans'l ◽  
M. Nielsen ◽  
R. L. Johnson

The atomic structure of the Au 6 × 6 on Si(111) phase has been determined using direct methods and surface X-ray diffraction data. This surface structure is very complicated, with 14 independent gold atoms, relaxations in 24 independent silicon sites and three partially occupied gold sites. In one sense the structure can be described as microdomains of the parent [Formula: see text] on Si(111) structure. A better description is in terms of a tiling of incomplete pentagonal and trimer units, essentially a pseudopentagonal glass. In terms of these structural units it appears possible to explain all the gold structures in the coverage range of 0.8–1.5 monolayers as pseudoglasses with strong short range order but varying degrees of long range order.


1975 ◽  
Vol 30 (12) ◽  
pp. 1633-1639 ◽  
Author(s):  
W. Hoyer ◽  
E. Thomas ◽  
M. Wobst

Abstract At temperatures just above the melting point molten Selenium seems to be a mixture of long chains and eight-membered rings. With increasing temperature the number of rings and the average chain length decrease. At 460 °C the average chain length lies in the range of 10 atoms.In a slightly supercooled Tellurium-melt the number of first neighbours is two. The atoms are arranged in chains. Selenium rich Se-Te-alloy-melts are built up of mixed chains. It seems to be possible, that a smaller part of atoms forms Se6Te2 rings. At Tellurium concentrations higher than approximately 50 at.-% the chainlike structure with two next nearest neighbours changes to a disturbed Arsen-like short range order. The number of electrons in the first coordination shell, the short range order parameter introduced by Cowley and the partial coordination numbers show that Se-Te-alloys are of the "solution system" type, but in the whole concentration range for each atom there is a tendency to have "strange coordination".


1987 ◽  
Vol 22 (12) ◽  
pp. 4357-4361 ◽  
Author(s):  
R. A. Ligero ◽  
J. Vázquez ◽  
P. Villares ◽  
R. Jimńez-Garay

Author(s):  
J. D. Londono ◽  
A. Habenschuss ◽  
J. G. Curro ◽  
J. J. Rajasekaran

2020 ◽  
Vol 56 (2) ◽  
pp. 269-277
Author(s):  
V.E. Sokol’skii ◽  
D.V. Pruttskov ◽  
O.M. Yakovenko ◽  
V.P. Kazimirov ◽  
O.S. Roik ◽  
...  

Anorthite and gehlenite crystalline structure and short-range order of anorthite melt have been studied by X-ray diffraction in the temperature range from room temperature up to ~ 1923 K. The corresponding anorthite and gehlenite phases were identified as well as amorphous component for anorthite samples having identical shape to XRD pattern of the anorthite melt. The structure factor and the radial distribution function of atoms of the anorthite melt were calculated from the X-ray high-temperature experimental data. The partial structural parameters of the short-range order of the melt were reconstructed using Reverse Monte Carlo simulations.


2002 ◽  
Vol 71 (10) ◽  
pp. 2456-2458 ◽  
Author(s):  
Dilip Kumar Saha ◽  
Toetsu Shishido ◽  
Ken-ichi Ohshima

1990 ◽  
Vol 195 ◽  
Author(s):  
J. Weissmüller ◽  
J. Jing ◽  
A. Krämer ◽  
R. Birringer ◽  
U. Gonser ◽  
...  

ABSTRACTA new method of preparing amorphous solids is presented. X-ray diffraction, thermal stability and Mgssbauer spectroscopy give evidence for an atomic structure with reduced short–range order in Si75Auz5 and Pd72FeloSil8 alloys prepared by this method.


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