Short range order of As40-xCuxTe60 (x=0, 10, 20, 25, 30) glasses was studied by neutron- and X-ray diffraction, combined with extended X-ray absorption fine structure (EXAFS) measurements at the ...K-edges of all components. Large-scale structural models were generated by fitting the experimental datasets simultaneously in the framework of the reverse Monte Carlo simulation technique. These simulations revealed that As and Te atoms bind to about 3 and 2 As/Te neighbors, respectively, both of which possess Cu neighbors. The CuTe bond length is 2.57±0.02Å while the CuAs distance is as high as 2.86±0.04Å. The results further showed that besides As and Te, Cu atoms also bind to Cu. The total coordination number of Cu is significantly higher than 4 for the compositions x=25 and 30.
•As and Te atoms bind to about 3 and 2 As/Te neighbors.•Both As and Te have Cu neighbors.•The total coordination number of Cu is significantly higher than 4 for As15Cu25Te60 and As10Cu30Te60.
Structural studies on AsSe–AgI glasses Petkova, T.; Petkov, P.; Jóvári, P. ...
Journal of non-crystalline solids,
06/2007, Letnik:
353, Številka:
18
Journal Article, Conference Proceeding
Recenzirano
The atomic structure of the binary AsSe, ternary (AsSe)
80Ag
20, (AsSe)
85I
15 and quaternary (AsSe)
65(AgI)
35 glasses has been studied with the X-ray and neutron diffraction. The local order was ...also probed with the extended X-ray absorption fine structure spectroscopy at Ag, As and Se K-edges. All experimental data were modeled simultaneously by the reverse Monte Carlo technique. Analysis of the partial pair distribution functions and their characteristics enabled to retrace the structural changes from binary AsSe to pseudo-binary (AsSe)
100−
x
(AgI)
x
system and to study the influence of Ag and I incorporation on the local structure.
The atomic structure of liquid Cu6Sn5 alloy at 640°C has been investigated with neutron and X-ray diffraction. The experimental structure factors were used to perform computer modeling with the ...reverse Monte Carlo method. Three different series of simulations were carried out. It has been established that the partial structure factors modeled by combining the experimental data of the two independent measurements (XRD and ND) are reliable, while those modeled with only one set of the experimental data (XRD or ND) exhibit some non-physical features.
The local atomic order of amorphous Se sub(1-x)S sub(x) alloys, x=0.20,0.30, produced by mechanical alloying were studied by Raman scattering, X-ray diffraction, EXAFS and reverse Monte Carlo ...simulations of their total structure factors and EXAFS oscillations on Se K edge. The results obtained were compared to those found for other Se sub(1-x)S sub(x), x=0,0.10 alloys, and the behavior of Raman modes, average coordination numbers and interatomic distances and bond-angle distribution functions as sulphur concentration increases were determined.
The parameters of the boson peak (BP) and the first sharp diffraction peak (FSDP) in (As2S3)x(GeS2)1x glasses measured using high-resolution Raman spectroscopy and high-energy synchrotron X-ray ...diffraction measurements are examined as a function of x. It has been found that there is no correlation between the positions of BP and FSDP. The BP position shows a nonlinear composition behavior with a maximum at about x = 0.4, whereas the FSDP position changes virtually linearly with x. The intensities of both BP and FSDP show nonlinear composition dependences with the slope changes at x = 0.4, although there is no direct proportionality. Analysis of the partial structure factors for the glasses with x = 0.2, 0.4 and 0.6 obtained in another study has shown that the cation-cation atomic pairs of Ge–Ge, Ge–As and As–As make the largest contribution to FSDP, where the Ge–Ge and Ge–As pairs are dominant.
Microstructure of (GeS3)100-xAgx (x = 0, 5, 10, 15, 20, 25) and (GeS2)100-xAgx (x = 0, 5, 10, 15, 20) has been studied by scanning electron microscopy. It is found that the glasses of both systems ...are phase separated: (GeS3)100-xAgx for 5 ≤ x ≤ 20 at.% and (GeS2)100-xAgx for 10 ≤ x ≤ 15 at.%. Morphology of coexisting phases is essentially dependent on the glass composition. The phase-separation is very pronounced in (GeS3)100-xAgx glasses and is diminished in (GeS2)100-xAgx as indicated by the size and spatial distribution of majority and minority phases.
The structure of binary (TiO
2)
x
(P
2O
5)
1−
x
glasses with
x
=
0.60, 0.65 and a ternary K
2O–TiO
2–P
2O
5 (KTP) glass were studied by X-ray and neutron diffraction. The experiments were performed ...at the high-energy beamline BW5 of the synchrotron DORIS (Hamburg/Germany) and at the GEM instrument of the neutron source ISIS (Chilton/UK). Gaussian fitting of well-resolved first-neighbor peaks in the correlation functions of the binary glasses with TiO
2 contents of 0.65 and 0.60 result in Ti–O coordination numbers of 5.65
±
0.2 and 5.9
±
0.2, respectively. Distorted TiO
6 octahedra and isolated PO
4 units form the glassy networks, with a small number of lower coordinated Ti sites for the 0.65 TiO
2 glass. For comparison, only TiO
6 octahedra are found for a ternary K
2O–TiO
2–P
2O
5 glass. The Ti–O coordination numbers are compared with a structural model where all oxygen atoms occupy sites in Ti–O–Ti, Ti–O–P or P–O–P bridges. The presence of three-coordinated oxygens must be assumed for the binary glasses, whereas a structure with nearly all oxygen atoms forming network bridges exists for the ternary KTP glass.
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