Low-temperature electrical conductivity of ternary chalcogenide glasses in the system Se–S

2002 ◽  
Vol 80 (5) ◽  
pp. 599-604 ◽  
Author(s):  
O El-Shazly ◽  
T Ramadan ◽  
M El-Hawary ◽  
N El-Anany ◽  
H A Motaweh ◽  
...  
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Low Temperature ◽  
Temperature Region ◽  
Chalcogenide Glasses ◽  
Measured Temperature ◽  
Exponential Factor ◽  
Ternary Chalcogenide ◽  
Extended States ◽  
Made In

Ternary chalcogenide glasses in the system Se–S were prepared by quenching from the melt. Measurements of the temperature dependence of direct current (dc) electrical conductivity have been made in the temperature interval from room temperature down to 30 K. Two types of conduction mechanisms were found to dominate in the measured temperature range, namely band conduction through extended states (which dominates at the high-temperature region) and hopping around the Fermi level (which dominates at the low-temperature region). The dc conductivity activation energy and pre-exponential factor were calculated for the two types of conduction. It was found that the activation energy and the pre-exponential factor are composition dependent. PACS Nos.: 72.20-i, 73.61.Jc, and 81.05.Gc

Macro Kinetics of N-Phosphonomethyliminodiacetic Acid Catalytic Oxidation

2012 ◽  
Vol 455-456 ◽  
pp. 872-879 ◽  
Author(s):  
Yan Bao ◽  
Jia Wu ◽  
Xiao Ping Hu
Keyword(s):  
Activation Energy ◽  
Kinetic Model ◽  
Measured Data ◽  
Second Step ◽  
Oxidizing Agent ◽  
Dissolved Oxygen Concentration ◽  
Exponential Factor ◽  
In Series ◽  
Kinetics Of ◽  
Made In

The oxidation of N-phosphonomethyliminodiacetic acid (PMIDA) to prepare glyphosate (PMG) over active carbon was investigated. Experiments were carried out with O2 as the oxidizing agent in a 150-mL autoclave made in stainless steel, with reaction temperature ranging from 323.15 to 353.25K and the pressure from 0.12 to 0.40 MPa. The macro kinetic model of the reactions in series was developed, and the pre-exponential factor and activation energy were estimated from the measured data in experiments. The influence of dissolved oxygen concentration was also considered in this macro kinetic model. The results indicated that the two step reactions are all one-order to reactant (PMIDA or PMG) and 0.3 or 0.07 to O2 respectively. The active energy was 12.98kJ/mol for the first step reaction and 10.87kJ/mol for the second step reaction.

Determination of the pre-exponential factor and the activation energy for the low-temperature dislocation relaxation in aluminum

2000 ◽  
Vol 310 (1-2) ◽  
pp. 107-110 ◽  
Author(s):  
Hirokazu Koizumi ◽  
Takaaki Koizumi ◽  
Toshio Kosugi
Keyword(s):  
Activation Energy ◽  
Low Temperature ◽  
Exponential Factor

Temperature and Composition Dependence of Electrical Conductivity of Ge10 Se90-x Bix (x=0, 2, 4, 6, 8, 10) Chalcogenide Glasses

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
Shiveom Srivastava ◽  
S. K. Srivastava ◽  
Krishna K. Srivastava ◽  
Narayan P. Srivastava
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Chalcogenide Glasses ◽  
Conduction Mechanism ◽  
Composition Dependence ◽  
Arrhenius Equation ◽  
Atomic Weight ◽  
Melt Quenching ◽  
Characteristic Curves ◽  
Glassy Systems

Electrical conductivity of Ge10 Se90-x Bix (x=0,2,4,6,8,10) glassy systems prepared by melt quenching technique has been studied at different temperature in bulk form through I-V characteristic curves. It has been observed that the electrical conductivity increases as the Bi concentration increases up to 4 atomic weight percentages and on further addition of Bi it reduces. The variation in electrical conductivity with Bi concentration is attributed to the Se-Bi bond concentration. Using the Arrhenius equation of conductivity, the activation energy of conduction is evaluated. The effect of Bi concentration on activation energy has also been studied. It is quite evident from results that Poole-Frankel and Rechardson-Schottky conduction mechanism hold good for conduction in these glasses.

Preparation and Characterization of TeO2 Based Glasses

2005 ◽  
Vol 480-481 ◽  
pp. 315-322 ◽  
Author(s):  
J. Pedlíková ◽  
J. Zavadil ◽  
Olga Prochazková ◽  
J. Kaluzny
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Low Temperature ◽  
Absorption Edge ◽  
Electronic Transitions ◽  
Transmission Range ◽  
Dc Electrical Conductivity ◽  
Pacs Codes ◽  
Low Temperature Photoluminescence

Binary and ternary TeO2 based oxy-chloride glass systems have been prepared and characterised by absorption and low-temperature photoluminescence spectroscopy, and by the measurements of dc electrical conductivity. Prepared glasses exhibit transmittance 75-80% in a broad transmission range 0.3 – 6.5µm with modest shift of upper absorption edge to longer wavelength as heavier ions are introduced into the system. Electronic transitions between 4f-4f inner shells of Pr3+ ions embedded into the host glass have been investigated in a wide temperature range as a function of used precursors used for doping. The temperature dependence of dc electrical conductivity exhibits Arrhenius plots with the single activation energy. PACS codes 81.05.Kf, 78.20.Ci, 78.55.Hx

Electrical and thermal properties of Na2SO4 doped with NaVO3, Ln2(SO4)3 (Ln = Eu, Pr)

1983 ◽  
Vol 61 (7) ◽  
pp. 1557-1561 ◽  
Author(s):  
Nobuhito Imanaka ◽  
Gin-Ya Adachi ◽  
Jiro Shiokawa
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Phase Transformation ◽  
Thermal Properties ◽  
Low Temperature ◽  
Apparent Activation Energy ◽  
Solid Electrolytes ◽  
A Value

In order to develop useful solid electrolytes for SO2 detectors, Na2SO4, Na2SO4–Eu2(SO4)3, Na2SO4–NaVO3, and Na2SO4–NaVO3–Ln2(SO4)3 (Ln = Eu, Pr) systems have been prepared, and their electrical and thermal properties have been measured. By doping Na2SO4 with Eu2(SO4)3, the electrical conductivity increases and the apparent activation energy of the Na2SO4–Eu2(SO4)3 system shows a value between those of Na2SO4-III and Na2SO4-I. Addition of NaVO3 and Ln2(SO4)3 (Ln = Eu, Pr) to Na2SO4 suppressed the phase transformation, by stabilizing the structure of the Na2SO4-I phase even at a relatively low temperature.

Effects of Microstructure on the Electrical Conductivity of SrCo0.8Fe0. 2O3_δ

1999 ◽  
Vol 575 ◽  
Author(s):  
K. Zhang ◽  
M. Miranova ◽  
Y. L. Yang ◽  
A. J. Jacobson ◽  
K. Salama
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Grain Size ◽  
Size Effect ◽  
Temperature Region ◽  
Grain Size Effect ◽  
Average Grain Size ◽  
Lower Temperature ◽  
Lower Temperature Region ◽  
Test Temperature Range

ABSTRACTThe effect of microstructure on the electrical conductivity of SrCO0.8Fe0.2O3_δ (SCFO) was investigated in air using a four-point dc method. In the test temperature range of 200 to 900 °C, the electrical conductivity of this material was observed to increase with the increase of the average grain size in the lower temperature region where the conductivity increases with the increase of the temperature. The activation energy is decreased with the increase of the grain size in this region, 0.04 ± 0.004 ev for 4.1μm sample and 0.01 ± 0.001 ev for 14.8 μm sample. When temperature is further increased, the conductivity of this material decreases with the increase of the temperature, and the grain size effect becomes less noticeable.

Chalcogenide Glasses

MRS Bulletin ◽  
1987 ◽  
Vol 12 (5) ◽  
pp. 36-39 ◽  
Author(s):  
P. Craig Taylor
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Electrical Properties ◽  
Periodic Table ◽  
Chalcogenide Glasses ◽  
Charge Carriers ◽  
Arsenic Trisulfide ◽  
Glass Forming ◽  
Optical Gap ◽  
Arsenic Triselenide

Although there are some significant exceptions, most important glass-forming systems contain elements from the sixth, or chalcogenide, column of the periodic table (oxygen, sulfur, selenium, or tellurium). The glasses which contain oxygen are typically insulators, while those which contain the heavier chalcogen elements are usually semiconductors. Even though oxygen is technically a chalcogen element, the term “chalcogenide glass” is commonly used to denote those largely covalent, semiconducting glasses which contain sulfur, selenium, or tellurium as one of the constituents.The chalcogenide glasses are called semiconducting glasses because of their electrical properties. The electrical conductivity in these glasses depends exponentially on the temperature with an activation energy which is approximately one half of the optical gap. In this sense these glasses exhibit electrical properties similar to those in intrinsic crystalline semiconductors. The analogy is by no means perfect. The mobilities for the charge carriers in these glasses are very low (< 10 cm2/V-s) compared to crystalline semiconductors, and there are even discrepancies in determining the sign of the charge carriers from measurements of the Hall effect and the Seebeck effect.The first detailed studies of the chalcogenide glasses were performed about 30 years ago. For many years the prototype compositions have been selenium (Se), arsenic triselenide (As2Se3) or arsenic trisulfide (As2S3), and germanium diselenide (GeSe2) or germanium disulfide (GeS2).

Electrophysical properties of the (SnSe)1−x–(SmSe)x solid solutions at high and low temperature

2019 ◽  
Vol 34 (01) ◽  
pp. 2050008
Author(s):  
V. A. Abdurahmanova ◽  
N. M. Abdullaev ◽  
Sh. S. Ismayilov
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Low Temperature ◽  
Solid Solutions ◽  
Low Temperatures ◽  
Electrophysical Properties ◽  
Type Specimens ◽  
Text Type ◽  
Donor Type ◽  
Text Density

The temperature range of [Formula: see text] = 77–770 K in the system alloys: Holl coefficient [Formula: see text], thermo-emf [Formula: see text], electric conductivity [Formula: see text], measured [Formula: see text]-density of components and analyzed. It has been established that samarium additive atoms contain donor-type properties and the effectiveness increases with the temperature increase: up to 40% proportional to [Formula: see text] K in [Formula: see text]-type specimens, whereas in [Formula: see text]-type samples this increase is higher and covers the contents of pH varying from [Formula: see text] to [Formula: see text]. An electrical conductivity of compounds increased due to the carrier activation with further increase of temperature. The activation energy of carriers at low temperatures ([Formula: see text] K) is [Formula: see text] eV for [Formula: see text] mol.% and [Formula: see text] mol.% compounds at [Formula: see text] = 77–320 K and for [Formula: see text] mol.% and [Formula: see text] mol.% compounds are [Formula: see text] eV. [Formula: see text] const at [Formula: see text]–400 K for [Formula: see text] mol.% and [Formula: see text] mol.% compounds, and passing with minimum increases at [Formula: see text] = 400–500 K.

Electrical Conductivity and Density of the Molten CaCl2-NaCl-Al2O3 Electrolyte Materials

2010 ◽  
Vol 152-153 ◽  
pp. 19-24
Author(s):  
Hong Wei Xie ◽  
Jin Xia Wang ◽  
Yu Chun Zhai ◽  
Cheng De Li ◽  
Xiao Yun Hu
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Low Temperature ◽  
Arrhenius Equation ◽  
Decisive Factor ◽  
Aluminium Electrolysis ◽  
Cell Constant ◽  
Measurement Temperature ◽  
Temperature Ranges ◽  
Function Relationship

The low-melting CaCl2-NaCl-Al2O3 materials were used as the electrolyte of the low temperature aluminium electrolysis. The electrical conductivity and density of the materials were measured by the Continuously Varying Cell Constant Technique, ac-techniques, and Archimedes method. The materials were composed of 71wt.%~87wt.%CaCl2 (corresponding NaCl), NaCl and Al2O3(without and saturated). The measurement temperature ranges were 550°C~800°C. The results showed that Additive Al2O3 decreased the electrical conductivity of the materials, and resulted in the increase of the activation energy of conductance. The function relationship between the electrical conductivity and temperature was linear, and conformed to the Arrhenius equation. Increasing the CaCl2 content decreased the electrical conductivity of the materials, but the density was increased. With the increase of the CaCl2, the decrease scope of the electrical conductivity was small and the increase trend of the density was slow down. The decisive factor of the electrical conductivity of the materials was temperature.

Effect of iron chloride on the polaronic conduction in potassium phosphateglasses containing iron oxide

2000 ◽  
Vol 78 (12) ◽  
pp. 1091-1105 ◽  
Author(s):  
Y M Moustafa
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Structural Changes ◽  
Small Polaron ◽  
Iron Chloride ◽  
Polaron Hopping ◽  
Exponential Factor ◽  
Order Of Magnitude ◽  
The Difference ◽  
Fe Ions

DC electrical conductivity measurements of Fe2O3–K2O–P2O5 glasses containing iron chloride have been carried out in the temperature range from room temperature to 360°C. The DC conductivity was analyzed in terms of small polaron hopping theory. The hopping regime between Fe ions was confirmed to be nonadiabatic. The increase in the conductivity was of the same order of magnitude as the change in the pre-exponential factor upon increasing the FeCl3 content. The decrease in the activation energy with increasing FeCl3 content was interpreted in terms of a decrease in the distance between the iron sites. The increase in electrical conductivity was ascribed to the difference in the activation energy. The variation in the conductivity parameters was interpreted in terms of the structural changes that take place upon increasing the FeCl3 content of the glasses. PACS No.72.20Ee

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