Semi-Empirical Fitting of Partial Pair Correlation Functions of Amorphous Alloys

1995 ◽  
Vol 50 (12) ◽  
pp. 1205-1218
Author(s):  
E. Sváb ◽  
F. Hajdu ◽  
Gy. Mészáros
Keyword(s):  
Amorphous Alloys ◽  
Structural Parameters ◽  
Pair Correlation ◽  
Analytical Formula ◽  
Partial Structure ◽  
Fitting Procedure ◽  
Atomic Pair ◽  
Structure Factors ◽  
Characteristic Features ◽  
Semi Empirical

Abstract A semi-empirical fitting procedure has been developed and used in analysing the characteristic features of the partial structure factors of binary amorphous alloys. An analytical formula is given to fit the experimental atomic pair correlation function as a sum of Gaussians. The inverse Fourier transform of the fitted terms reproduces all features of the experimental structure function. In addition to the structural parameters, the modelling gives a quantitative explanation for the complex origin of characteristic features in the diffraction pattern such as pre-peak, pre-minimum, and split peaks in the partial structure factor.

Electron Diffraction with the Amorphous Alloys Fe80B20 and Mn73Si27

1982 ◽  
Vol 37 (11) ◽  
pp. 1215-1222
Author(s):  
F. Paasche ◽  
H. Olbrich ◽  
G. Rainer-Harbach ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Electron Diffraction ◽  
Neutron Diffraction ◽  
Amorphous Alloys ◽  
Pair Correlation ◽  
Diffraction Experiment ◽  
Partial Structure ◽  
Neutron Diffraction Experiment ◽  
X Ray ◽  
Structure Factors ◽  
Beam Experiment

Electron diffraction with amorphous Fe80B20 and Mn73Si27 yields structure factors and pair correlation functions which are discussed together with the results of X-ray- and neutron-diffraction experiments. For Mn73Si27 additional interesting details are revealed. A tetrahedral model for Mn73Si27 is described. Finally we show that the evaluation of partial structure factors by the three beam experiment, i.e. the combination of an electron-, X-ray- and neutron-diffraction experiment is not possible in general.

A method for determination of partial structure factors of binary amorphous alloys

1990 ◽  
Vol 126 (3) ◽  
pp. 239-248 ◽  
Author(s):  
G.H. Bezerra ◽  
L.Q. Amaral ◽  
A.F. Craievich ◽  
D. Raoux
Keyword(s):  
Amorphous Alloys ◽  
Partial Structure ◽  
Structure Factors

New methods of processing of anomalous X-ray scattering data for amorphous alloys I. Determination of partial structure factors

1990 ◽  
Vol 119 (2) ◽  
pp. 159-172 ◽  
Author(s):  
Yu.A. Babanov ◽  
R.Sh. Sadykova ◽  
V.R. Shvetsov ◽  
A.V. Serikov ◽  
A.L. Ageev ◽  
...  
Keyword(s):  
Amorphous Alloys ◽  
Scattering Data ◽  
Partial Structure ◽  
X Ray ◽  
New Methods ◽  
X Ray Scattering ◽  
Structure Factors ◽  
Ray Scattering

Partial Structure Factors in Multicomponent Liquid or Amorphous Alloys

1976 ◽  
Vol 31 (8) ◽  
pp. 960-966 ◽  
Author(s):  
J. Blétry
Keyword(s):  
Amorphous Alloy ◽  
Amorphous Alloys ◽  
Sum Rules ◽  
Chemical Species ◽  
Partial Structure ◽  
Static Approximation ◽  
Isotropic Approximation ◽  
Structure Factors ◽  
Limiting Values

AbstractThe structure of a υ component liquid or amorphous alloy is analyzed in terms of υ(υ+1)/2 independent partial structure factors which are associated to the different correlations between the numbers of particles of all chemical species. This formalism, which is specially adapted to the study of alloys of more than two components, is related to Fournet-Faber-Ziman and extended Bhatia-Thornton theory. Sum rules, inequality relations and limiting values are calculated in the static approximation and Debye pair expressions of the structure factors are derived in the isotropic approximation.

scholarly journals Structural disordering in Sn-Pb(Bi) eutectic melts induced by heating

2013 ◽  
Vol 15 (3) ◽  
pp. 61-64 ◽  
Author(s):  
S. Mudry ◽  
I. Shtablavyi ◽  
I. Shevernoga
Keyword(s):  
Melting Point ◽  
Structural Parameters ◽  
Pair Correlation ◽  
Cluster Structure ◽  
Eutectic Alloys ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Factors ◽  
Different Types ◽  
Structural Disordering

Abstract The structure of liquid Sn0.739Pb0.261 and Sn0.57Bi0.43 eutectic alloys was studied by means of X-ray diffraction at several temperatures. Structure factors, pair correlation functions and the main structural parameters obtained on their basis were analyzed. We show that the structure of the Sn0.739Pb0.261 and Sn0.57Bi0.43 eutectic alloys is inhomogeneous and consists of different types of clusters. Upon heating the cluster structure undergoes topological and chemical disordering showing a significant dependence of structural parameters on temperature near the melting point

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.

Structure of the Molten 37 a/o Cu-63 a/o Sb Alloy Using the Isotopic Substitution Method in Neutron Diffraction

1978 ◽  
Vol 33 (4) ◽  
pp. 472-479 ◽  
Author(s):  
W. Knoll ◽  
S. Steeb
Keyword(s):  
Neutron Diffraction ◽  
Pair Correlation ◽  
Neutron Diffraction Study ◽  
Number Density ◽  
Partial Structure ◽  
Distance Correlation ◽  
Structure Factors ◽  
Total Structure ◽  
The Fourier Transform ◽  
Strong Segregation

A neutron diffraction study of the eutectic Cu-Sb-melt containing 37 a/o Cu has been performed using isotopically enriched samples. The three partial structure factors describing the Cu-Cu, Cu-Sb, and Sb-Sb correlations have been determined as well as a second set of partial structure factors relating to the distance correlation of fluctuations in number density and concentration. Unsmoothed total structure factors were used. By Fourier-transformation the corresponding pair correlation functions were obtained. A strong segregation tendency was found. Concentration fluctuations with a correlation length of 2.4 Å could be determined. From the Fourier-transform of SCC the product N̄1α1 was obtained confirming the segregation tendency. The distance of nearest Cu-Cu neighbours in the eutectic Cu-Sb melt was found to be smaller than in pure molten Cu, whereas the Sb-Sb distance is larger than in pure Sb. According to Faber-Ziman theory the electrical resistivity was calculated and compared with experimental data.

Determination of Partial Structure Factors of Molten Eutectic Ni33Ge67

1993 ◽  
Vol 48 (3) ◽  
pp. 452-456
Author(s):  
Th. Halm ◽  
W. Hoyer ◽  
H. Neumann ◽  
R. Bellissent
Keyword(s):  
Pair Correlation ◽  
Coordination Shell ◽  
Isotopic Substitution ◽  
Overdetermined System ◽  
Partial Structure ◽  
X Ray ◽  
X Ray Scattering ◽  
Structure Factors ◽  
Degree Of Charge Transfer

Abstract Using isotopic substitution and X-ray scattering, different weighted structure factors were measured and combined in order to calculate partial structure factors. Although we got an overdetermined system of equations, the solution of this problem was difficult due to the small value of the determinant. From the partial pair correlation functions and the radial concentration correlation function a splitting of the first coordination shell is obvious. The dip in SNi-Ge and the corresponding peak in SNi-Ni indicate some degree of charge transfer in the melt.

Direct Fitting of Grazing-Incidence Neutron and X-ray Reflectivity Profiles using the Kinematic Approximation

1995 ◽  
Vol 28 (5) ◽  
pp. 518-526 ◽  
Author(s):  
E. M. Lee ◽  
J. E. Milnes
Keyword(s):  
Fourier Transforms ◽  
Molecular Geometry ◽  
Grazing Incidence ◽  
Partial Structure ◽  
Ion Distribution ◽  
X Ray ◽  
Reflection Data ◽  
Fitting Procedure ◽  
Structure Factors ◽  
Kinematic Approximation

At present, neutron and X-ray reflection data have been analysed either by modelling, using the optimal-matrix method, or by the fitting of partial structure factors arising from application of the kinematic approximation. Here the direct and simultaneous fitting of neutron and X-ray reflection profiles measured for a series of isotopic variations of the same interface is described. The interface is described as consisting of several components, which are either groups of atoms in a molecule or a whole molecule itself. In this work, the density distributions of the components perpendicular to the interface are described as Gaussian or tanh functions. These forms are chosen because they have analytical Fourier transforms. Fitting reflectivity profiles rather than partial structure factors reduces the sensitivity of the analysis to imperfections in one or more data sets. With existing kinematic methods, it is difficult to combine X-ray and neutron measurements. The new method readily allows such a combination, which is of importance if the capacity for isotopic substitution is limited or information about the counter-ion distribution is desired. It is also demonstrated that constraints posed by the stoichiometry of the interfacial species, by volume filling and molecular geometry, or from the results of the application of other experimental techniques, may readily be incorporated into the new fitting procedure.

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