Influence of annealing on the electrical conductivity of single crystals of Cu2O

1970 ◽  
Vol 48 (1) ◽  
pp. 63-69 ◽  
Author(s):  
F. L. Weichman ◽  
R. Kužel
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Low Temperature ◽  
Single Crystals ◽  
Activation Energies ◽  
Conductivity Measurements ◽  
Different Temperatures ◽  
Temperature Activation ◽  
The Stability ◽  
Stability Ranges

A series of conductivity measurements were made on single crystals of Cu2O from 20 to 840 °C to explain the various activation energies which appear at different temperatures and oxygen pressures. Crystals were annealed in the 10−8 and 10−4 Torr region in the stability ranges of Cu2O, Cu, and CuO at various temperatures. For the low-temperature activation energies ranging from 0.60 to 0.26 eV, an excellent agreement with the empirical Meyer–Neldel rule was found. The highest activation energy of 1.12 eV in the 570 to 680 °C range at 10−8 Torr is associated with the boundary between the two stable phases Cu and Cu2O. The changes in defect concentration are ascribed to the mechanism of self-compensation. The energy-level diagram proposed by Bloem is adequate to explain the present results.

scholarly journals Analysis of X-ray structure, dielectric properties and AC conductivity of (4E)-2-amino-3-cyanobenzo[b]oxocin-6-one

2016 ◽  
Vol 34 (2) ◽  
pp. 386-392 ◽  
Author(s):  
H.A.M. Ali ◽  
Magdy A. Ibrahim
Keyword(s):  
Crystal Structure ◽  
Activation Energy ◽  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Relaxation Time ◽  
Conductivity Measurements ◽  
X Ray Diffraction ◽  
Ac Electrical Conductivity ◽  
X Ray ◽  
Different Temperatures

AbstractThe crystal structure of (4E)-2-amino-3-cyanobenzo[b]oxocin-6-one, denoted as 4(E)-ACBO, was analyzed using X-ray diffraction technique. The dielectric and AC electrical conductivity measurements of the bulk 4(E)-ACBO in the form of pellet were studied in the range of frequency 42 Hz to 5 MHz and the temperature range of 303 K to 373 K. The temperature and frequency dependence of dielectric constant (∊1), dielectric loss (∊2) and AC electrical conductivity (σAC) were investigated. The relaxation time (τ) for electrons to hop over a barrier of height WH was calculated at different temperatures. The AC activation energy was determined from the temperature dependence of σAC at different frequencies.

scholarly journals A Comparative Evaluation of Physicochemical Properties and Photocatalytic Efficiencies of Cerium Oxide and Copper Oxide Nanofluids

Catalysts ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 34 ◽  
Author(s):  
Rashmi M. ◽  
Padmanaban R. ◽  
Vaithinathan Karthikeyan ◽  
Vellaisamy A. L. Roy ◽  
Anantha-Iyengar Gopalan ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Activation Energy ◽  
Electrical Conductivity ◽  
Physicochemical Properties ◽  
Copper Oxide ◽  
Cerium Oxide ◽  
Ac Conductivity ◽  
Morphological Properties ◽  
Different Temperatures ◽  
The Stability

Copper oxide (CuO) and cerium oxide (CeO2) of various concentrations have been prepared through an ultrasonically assisted dispersion of CuO and CeO2 nanoparticles (NPs) in which water and nanofluids (NFs) were formulated. The morphological properties of the CuO and CeO2 NPs are reported. Few of the physicochemical properties that can influence the photocatalytic activities of the NFs are evaluated, such as viscosity, activation energy, density, thermal conductivity, electrical conductivity, alternating current (AC) conductivity, pH, stability, refractive index and optical band gap of the CuO and CeO2 NFs. Viscosity studies have been made at four different temperatures (303 K, 308 K, 313 K and 318 K) and the activation energy is calculated and compared between the CuO and CeO2 NFs. The thermal conductivity of the two NFs is calculated and compared. Electrical conductivity is measured for CuO and CeO2 NFs using an impedance analyzer at different frequencies at 303 K. The dielectric constant and AC conductivity were studied. The electrical conductivity and pH of the prepared NFs are measured and the results are compared. The stability of the NFs is determined from Zeta potential values obtained from dynamic light scattering measurements. UV-Visible diffuse reflectance measurements were used to deduce the optical bandgap of the respective metal oxide NPs in the NFs. The photocatalytic efficiencies of the CuO NFs and CeO2 NFs were evaluated using methylene blue (MB) as the model dye. The rate constant for the photodegradation of MB was higher for CuO NF as compared CeO2 NF and also higher than simple NPs-based photocatalysts. A plausible explanation for the role of NFs over the simple NPs-based photocatalytic solution is presented.

Low Temperature Relay Modulator for Thermal and Electrical Conductivity Measurements

1967 ◽  
Vol 38 (3) ◽  
pp. 428-429 ◽  
Author(s):  
M. H. Jericho ◽  
R. H. March
Keyword(s):  
Electrical Conductivity ◽  
Low Temperature ◽  
Conductivity Measurements

INFLUENCE OF THE CROSSLINK STRUCTURE ON THE ACTIVATION ENERGY CALCULATED UNDER THERMO-OXIDATIVE CONDITIONS

2018 ◽  
Vol 91 (1) ◽  
pp. 205-224 ◽  
Author(s):  
Richard J. Pazur ◽  
T. Mengistu
Keyword(s):  
Activation Energy ◽  
Zinc Oxide ◽  
High Temperature ◽  
Oxidation Process ◽  
Activation Energies ◽  
Structure Stability ◽  
Temperature Oxidation ◽  
Network Chain ◽  
Temperature Activation ◽  
Sulfur Donor

ABSTRACT A series of six carbon black reinforced brominated poly(isobutylene-co-isoprene) (BIIR) compounds has been developed varying only in cure system type: sulfur, sulfur donor, zinc oxide, peroxide, phenolic resin, and ionic. Compounds were aged from room temperature up to 115 °C, and hardness, mechanical properties, and network chain density were measured. Non-Arrhenius behavior was observed due to data curvature from 70 to 85 °C. The oxidation process was adequately described by assigning low (23–85 °C) and high (85–115 °C) temperature regimes. Heterogeneous aging due to diffusion limited oxygen (DLO) occurred for heat aging above 85 °C, and all measured responses except tensile strength were strongly affected, causing lower activation energies. The activation energy for the high temperature oxidation process is in the range of 107 to 133 kJ/mol in the following ascending order: zinc oxide, ionic, sulfur donor, sulfur, peroxide, and resin. The midpoint of the high temperature activation energies is of the same order as the BIIR and poly(isobutylene) elastomers. The low temperature activation energy is in the range of 55–60 kJ/mol and is likely due to a combination of oxidative chain scission (crosslink density loss) and crosslinking recombination (network building) reactions. Apart from the crosslink structure stability, the presence of unsaturation along the polymer chain after vulcanization affects the high temperature activation energy.

Conductivities of Room Temperature Molten Salts Containing ZnCl2, Measured by a Computerized Direct Current Method

2002 ◽  
Vol 57 (3-4) ◽  
pp. 129-135
Author(s):  
Hsin-Yi Hsu ◽  
Chao-Chen Yang
Keyword(s):  
Activation Energy ◽  
Direct Current ◽  
Molten Salts ◽  
Room Temperature ◽  
Current Method ◽  
Cross Linking ◽  
Infra Red ◽  
Different Temperatures ◽  
The Stability ◽  
Benzyltriethylammonium Chloride

The conductivities of the binary room-temperature molten salt (RTMS) systems ZnCl2-N-nbutylpyridinium chloride (BPC), ZnCl2 -1-ethyl-3-methylimidazolium chloride (EMIC) and ZnCl2 - benzyltriethylammonium chloride (BTEAC) have been measured at different temperatures and compositions by a d.c. four-probes method. The conductivities of the three RTMS are in the order ZnCl2-EMIC > ZnCl2-BPC > ZnCl2-BTEAC. In ZnCl2-BPC the conductivity at 70 to 150 °C, is maximal for 40 mol% ZnCl2. In ZnCl2 - EMIC, the conductivity below 130 °C is almost constant for 30 to 50 mol% ZnCl2 and has the lowest activation energy 25.21 kJ/mol. For these two systems, the conductivities decrease rapidly beyond 50 mol% ZnCl2 owing to the rapid increase in cross-linking and resultant tightening of the polyelectrolyte structure. As to the ZnCl2-BTEAC system, the conductivities at 110 - 150 °C decrease slowly for 30 - 60 mol% ZnCl2. The conductivities of the ZnCl2-EMICmelt are compared with those of the AlCl3-EMIC melt previously studied. The stability of the ZnCl2-EMIC melt system is explored by the effect of the environment on the conductivity and the Far Transmission Infra Red (FTIR) spectrum. It reveals that the effect is slight, and that the ZnCl2-EMIC melt may be classified as stable.

scholarly journals The Stability of Icosahedral Cd-Yb

2003 ◽  
Vol 805 ◽  
Author(s):  
Günter Krauss ◽  
Sofia Deloudi ◽  
Andrea Steiner ◽  
Walter Steurer ◽  
Amy R. Ross ◽  
...  
Keyword(s):  
Low Temperature ◽  
Ambient Temperature ◽  
Mechanical Stress ◽  
Single Crystals ◽  
High Temperatures ◽  
Low Temperatures ◽  
Ambient Pressure ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Stability

ABSTRACTThe stability of single-crystalline icosahedral Cd-Yb was investigated using X-ray diffraction methods in the temperature range 20 K ≤ T ≤ 900 K at ambient pressure and from ambient temperature to 873 K at about 9 GPa. Single-crystals remain stable at low temperatures and in the investigated HP-HT-regime. At high temperatures and ambient pressure, the quasicrystal decomposes. The application of mechanical stress at low temperatures yields to the same decomposition, the formation of Cd. A reaction of icosahedral Cd-Yb with traces of oxygen or water causing the decomposition seems reasonable, but a low-temperature instability of this binary quasi-crystal cannot be ruled out totally.

Impurity-Induced Defect States in Pb1−xGexTe Alloys Doped With Gallium

1999 ◽  
Vol 607 ◽  
Author(s):  
E.P. Skipetrov ◽  
E.A. Zvereva ◽  
V.V. Belousov ◽  
L.A. Skipetrova
Keyword(s):  
Low Temperature ◽  
Heat Source ◽  
Single Crystals ◽  
Deep Level ◽  
Persistent Photoconductivity ◽  
Background Illumination ◽  
Defect States ◽  
Galvanomagnetic Properties ◽  
Controlled Illumination ◽  
Temperature Activation

AbstractGalvanomagnetic properties of n-Pb1−xGexTe<Ga>(O.04≤x≤O.08) single crystals have been investigated in the shielded from external background illumination chamber and under controlled illumination from infrared heat source. Low temperature activation range of the impurity conductivity on the dark curves of ρ(l/T) was revealed and attributed to the appearance of gallium-induced deep level EGa in the gap of the alloys. It was shown that the alloys possess high infrared photosensitivity at temperatures below Tc=50%60 K, and effect of the persistent photoconductivity at helium temperatures was revealed.

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.

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