Thermodynamics of mixing and ordering in the diopside–jadeite system: II. A polynomial fit to the CVM results

2002 ◽  
Vol 66 (4) ◽  
pp. 537-545 ◽  
Author(s):  
V. L. Vinograd
Keyword(s):  
Solid Solution ◽  
Free Energy ◽  
Short Range ◽  
Gaussian Functions ◽  
Equilibrium Computation ◽  
Polynomial Fit ◽  
Short Range Ordering ◽  
Thermodynamics Of Mixing ◽  
Long Range Ordering ◽  
The Relationship

AbstractIn Part I (Vinograd, 2002) the relationship between temperature, composition and free energy of the diopside–jadeite solid solution was described using a CVM model. Here the same relationship is described using a combination of Redlich-Kister (RK) polynomials and Gaussian functions. The use of the Gaussians permits an accurate description of the free energy dip centred at Jd50, which is caused by the long-range ordering, while the effect of the short-range ordering can be easily modelled using the RK polynomial The simplified RK-Gaussian description is extended to the three-component diopside–jadeite–hedenbergite solid solution. The polynomial description permits an easy incorporation of the derived activity-composition relations into phase-equilibrium computation software.

Emulation of short-range ordering within the Compound Energy Formalism: Application to the calcite-magnesite solid solution

Calphad ◽  
2019 ◽  
Vol 64 ◽  
pp. 115-125 ◽  
Author(s):  
Xin Liu ◽  
Victor L. Vinograd ◽  
Sergii Nichenko ◽  
Dmitrii A. Kulik ◽  
Xiancai Lu ◽  
...  
Keyword(s):  
Solid Solution ◽  
Short Range ◽  
Compound Energy Formalism ◽  
Short Range Ordering

Sc Modification Induced Short-range Ordering in ZnGa2O4 Spinel Leading to High Microwave Dielectric Performance

2020 ◽  
Author(s):  
xiaochi Lu ◽  
Bin Quan ◽  
Kailai Zheng ◽  
Peng Chu ◽  
Jian Wang ◽  
...  
Keyword(s):  
Short Range ◽  
Microwave Dielectric Properties ◽  
Solid State Method ◽  
Microwave Dielectric ◽  
Governing Factor ◽  
Short Range Ordering ◽  
Dielectric Performance ◽  
Ft Ir ◽  
Ir Analysis ◽  
The Relationship

Abstract Sc3+ (0,0.1,0.3,0.5,0.7mol%) modified ZnGa2O4 (abbreviated Sc-ZGO) ceramics were synthesized by solid-state method. The relationship between microwave dielectric performance and bonds vibration of Sc-ZGO as a function of Sc3+ modification has been systematically investigated. With Sc3+ modification, the εr of Sc-ZGO ceramics keeps steady (~10). While the τf of Sc-ZGO shows linear correlation with Sc3+ concentration increasing from -71ppm/℃ to -39ppm/℃, and the Q×f value climbs up to a maximum value (5Sc-ZGO) and then ramp down. 5Sc-ZGO sintered at 1350oC for 2 h exhibits the best microwave dielectric properties with εr = 9.9, Q×f = 124,147 GHz, tanδ = 7.98×10-5, and τf = -56 ppm/°C (@9.9 GHz). Q×f value of Sc modified ZGO increased by almost 45% compared with normal spinel ZnGa2O4 ceramics. The enhancement of τf and Q×f on Sc modified ZnGa2O4 can be attributed to higher densification, however, further Raman and FT-IR analysis elucidated that short-range cation ordering degree is another governing factor. The influence of Sc3+ modification on ZnGa2O4 bonds vibration has been discussed in detail.

Temperature dependence of the resistivity of Hg3–δAsF6

1982 ◽  
Vol 60 (9) ◽  
pp. 1348-1357 ◽  
Author(s):  
E. Batalla ◽  
W. R. Datars
Keyword(s):  
Fermi Surface ◽  
Temperature Dependence ◽  
Electron Scattering ◽  
Short Range ◽  
Linear Chain ◽  
Three Dimensional ◽  
One Dimensional ◽  
Anisotropic Superconductor ◽  
Short Range Ordering ◽  
Long Range Ordering

The resistivity of the linear-chain mercury compound Hg3–δAsF6 is reported in the temperature range 1.4–300 K. Electron scattering by one-dimensional and three-dimensional phonons on a cylindrical Fermi surface is used to calculate the temperature dependence of the resistivity which agrees with measurements of the resistivity between 4.2 and 90 K. The resistivity is determined by the Montgomery method which is extended to the case when electrical probes are not at the corners of a sample. The anisotropy ρc/ρa of the resistivity is in the range 95 ± 10 between 40 and 180 K. It is explained by a 1.4% undulation along the Fermi surface cylinders. Changes in the anisotropy give evidence of three-dimensional, long-range ordering at 120 K and short-range ordering of the mercury chains between 180 and 200 K reported previously. Hysteresis in the resistivity shows an unusual transition at 217 ± 3 K which is evident only upon cooling samples. There is no evidence of zero, c-axis resistivity below 4.1 K to support the suggestion that Hg3–δAsF6 is an anisotropic superconductor.

Long-range and short-range ordering of hydrogen or deuterium atoms in solid solution in yttrium

1987 ◽  
Vol 129 ◽  
pp. 287-295 ◽  
Author(s):  
J.E. Bonnet ◽  
D.K. Ross ◽  
D.A. Faux ◽  
I.S. Anderson
Keyword(s):  
Solid Solution ◽  
Long Range ◽  
Short Range ◽  
Short Range Ordering

scholarly journals Calphad Modeling of LRO and SRO Using ab initio Data

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 998
Author(s):  
Masanori Enoki ◽  
Bo Sundman ◽  
Marcel H. F. Sluiter ◽  
Malin Selleby ◽  
Hiroshi Ohtani
Keyword(s):  
Experimental Data ◽  
Dft Calculations ◽  
Short Range ◽  
State Of The Art ◽  
Model Parameters ◽  
Experimental Uncertainty ◽  
Calphad Technique ◽  
Calphad Modeling ◽  
Short Range Ordering ◽  
Long Range Ordering

Results from DFT calculations are in many cases equivalent to experimental data. They describe a set of properties of a phase at a well-defined composition and temperature, T, most often at 0 K. In order to be practically useful in materials design, such data must be fitted to a thermodynamic model for the phase to allow interpolations and extrapolations. The intention of this paper is to give a summary of the state of the art by using the Calphad technique to model thermodynamic properties and calculate phase diagrams, including some models that should be avoided. Calphad models can decribe long range ordering (LRO) using sublattices and there are model parameters that can approximate short range ordering (SRO) within the experimental uncertainty. In addition to the DFT data, there is a need for experimental data, in particular, for the phase diagram, to determine the model parameters. Very small differences in Gibbs energy of the phases, far smaller than the uncertainties in the DFT calculations, determine the set of stable phases at varying composition and T. Thus, adjustment of the DFT results is often needed in order to obtain the correct set of stable phases.

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