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.

scholarly journals SYNTHESIS AND ELECTRICAL CONDUCTIVITY OF SOLID SOLUTIONS OF THE SYSTEM RbF-PbF2-SnF2

2019 ◽  
Vol 85 (5) ◽  
pp. 60-68
Author(s):  
Yuliay Pogorenko ◽  
Anatoliy Omel’chuk ◽  
Roman Pshenichny ◽  
Anton Nagornyi
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Temperature Dependence ◽  
Solid Solutions ◽  
Basic Structure ◽  
Elementary Cell ◽  
Initial Structure ◽  
Fluoride Ions ◽  
Temperature Range ◽  
Order Of Magnitude

In the system RbF–PbF2–SnF2 are formed solid solutions of the heterovalent substitution RbxPb0,86‑xSn1,14F4-x (0 < x ≤ 0,2) with structure of β–PbSnF4. At x > 0,2 on the X-ray diffractograms, in addition to the basic structure, additional peaks are recorded that do not correspond to the reflexes of the individual fluorides and can indicate the formation of a mixture of solid solutions of different composition. For single-phase solid solutions, the calculated parameters of the crystal lattice are satisfactorily described by the Vegard rule. The introduction of ions of Rb+ into the initial structure leads to an increase in the parameter a of the elementary cell from 5.967 for x = 0 to 5.970 for x = 0.20. The replacement of a part of leads ions to rubium ions an increase in electrical conductivity compared with β–PbSnF4 and Pb0.86Sn1.14F4. Insignificant substitution (up to 3.0 mol%) of ions Pb2+ at Rb+ at T<500 K per order of magnitude reduces the conductivity of the samples obtained, while the nature of its temperature dependence is similar to the temperature dependence of the conductivity of the sample β-PbSnF4. By replacing 5 mol. % of ions with Pb2+ on Rb+, the fluoride ion conductivity at T> 450 K is higher than the conductivity of the initial sample Pb0,86Sn1,14F4 and at temperatures below 450 K by an order of magnitude smaller. With further increase in the content of RbF the electrical conductivity of the samples increases throughout the temperature range, reaching the maximum values at x≥0.15 (σ573 = 0.34–0.41 S/cm, Ea = 0.16 eV and σ373 = (5.34–8.16)•10-2 S/cm, Ea = 0.48–0.51 eV, respectively). In the general case, the replacement of a part of the ions of Pb2+ with Rb+ to an increase in the electrical conductivity of the samples throughout the temperature range. The activation energy of conductivity with an increase in the content of RbF in the low-temperature region in the general case increases, and at temperatures above 400 K is inversely proportional decreasing. The nature of the dependence of the activation energy on the concentration of the heterovalent substituent and its value indicate that the conductivity of the samples obtained increases with an increase in the vacancies of fluoride ions in the structure of the solid solutions.

Low temperature photoconductivity in a-ZnSe

1977 ◽  
Vol 55 (24) ◽  
pp. 2142-2144 ◽  
Author(s):  
D. E. Brodie ◽  
P. K. Lim ◽  
R. T. S. Shiah
Keyword(s):  
Activation Energy ◽  
Low Temperature ◽  
Low Temperatures

At lower temperatures, the photoconductivity of near stoichiometric or slightly selenium-rich a-ZnSe increases with an activation energy of 0.04 eV as the temperature decreases. Slightly Zn-rich samples do not exhibit this behaviour. This paper presents a model and a possible mechanism for this effect, which involves intimate valence alternation pairs as the controlling recombination centres at low temperatures. A similar effect has been observed in tellurium-rich a-CdTe.

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.

A Low Temperature Infrared Study of Self-association in Thiols

1972 ◽  
Vol 50 (22) ◽  
pp. 3594-3600 ◽  
Author(s):  
R. Bicca de Alencastro ◽  
C. Sandorfy
Keyword(s):  
Hydrogen Bonding ◽  
Low Temperature ◽  
Infrared Spectra ◽  
Low Temperatures ◽  
Infrared Study ◽  
Text Type ◽  
Stretching Vibration ◽  
Aliphatic Thiols ◽  
Self Association ◽  
Associated Species

The infrared spectra of several aliphatic thiols and of benzenethiol were measured between 2400 and 2700 cm−1, and 4800 and 5300 cm−1 in a 1:1 mixture of CCl3F and C2F4Br2, at temperatures ranging from 20 to −190 °C. Dimerization takes place at low temperatures and more highly associated species also appear. Free S—H groups are present in the solutions as well as in the pure liquids, even at the lowest temperatures. The association is of the [Formula: see text] type in aliphatic thiols; both [Formula: see text] and [Formula: see text] bonds are found in the case of benzenethiol and α-toluenethiol. Hydrogen bonding has little effect on the anharmonicity of the S—H stretching vibration.

Impurity Conduction in Silicon Carbide

2007 ◽  
Vol 556-557 ◽  
pp. 367-370 ◽  
Author(s):  
Michael Krieger ◽  
Kurt Semmelroth ◽  
Heiko B. Weber ◽  
Gerhard Pensl ◽  
Martin Rambach ◽  
...  
Keyword(s):  
Activation Energy ◽  
Low Temperature ◽  
Low Temperatures ◽  
Nearest Neighbor ◽  
Arrhenius Plot ◽  
Schottky Contacts ◽  
Steep Slope ◽  
Admittance Spectroscopy ◽  
Resistivity Measurements ◽  
Impurity Conduction

We report on admittance spectroscopy (AS) investigations taken on aluminum (Al)- doped 6H-SiC crystals at low temperatures. Admittance spectra taken on Schottky contacts of highly doped samples (NA ≥ 7.2×1017 cm-3) reveal two series of conductance peaks, which cause two different slopes of the Arrhenius plot. The steep slope is attributed to the Al acceptor, while the flatter one - obtained from the low temperature peaks - is attributed to the activation energy ε3 of nearest neighbor hopping. We propose a model, which explains the unexpected sharpness of the low temperature conductance peaks and the disappearance of these peaks for low acceptor concentrations. The model is verified by simulation, and the AS results are compared with corresponding results obtained from resistivity measurements taken on 4H- and the identical 6HSiC samples.

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.

scholarly journals Low-Temperature Sintering of Apatite-Type Lanthanum Silicate with Fluoride Additives

2010 ◽  
Vol 62 ◽  
pp. 235-240
Author(s):  
Junichi Takahashi ◽  
Hidetoshi Honda ◽  
Takaya Akashi ◽  
Kazutomo Abe ◽  
Hidenobu Itoh ◽  
...  
Keyword(s):  
Activation Energy ◽  
Liquid Phase ◽  
Low Temperature ◽  
Bulk Density ◽  
Grain Growth ◽  
Low Temperatures ◽  
Abnormal Grain Growth ◽  
Low Temperature Sintering ◽  
Lanthanum Silicate ◽  
Apatite Type

Various fluorides (3 - 8 wt%) were added to a La9.33Si6O26 (LSO) powder synthesized by calcining the corresponding oxides mixture at 1100°C for 4 h. The addition of BaF2, AlF3 or Ba3Al2F12 caused an appreciable and substantial increase in bulk density after sintering at 1400º and 1450°C, respectively. These fluorides melt below 1400°C to form liquid phase which could assist the densification at low temperatures. Abnormal grain growth was observed for LSO samples with the addition of AlF3 and Ba3Al2F12, but it was effectively suppressed by stepwise sintering at 1400º and 1450°C. The BaF2 addition brought about the simultaneous promotion of densification and moderate grain growth, leading to the production of a densified LSO sample showing a conductivity of 1.5 x 10–2 Scm–1 at 800°C with an activation energy of 1.23 eV.

scholarly journals SYNTHESIS AND ELECTRICAL CONDUCTIVITY OF SOLID SOLUTIONS OF THE SYSTEM PbF2–NdF3–SnF2

2020 ◽  
Vol 86 (5) ◽  
pp. 24-37
Author(s):  
Pohorenko Yuliia ◽  
Omel’chuk Anatoliy ◽  
Nagornyi Anton
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Solid Solutions ◽  
Basic Structure ◽  
Elementary Cell ◽  
Initial Structure ◽  
Temperature Range ◽  
The Individual ◽  
Increasing Temperature ◽  
Transfer Numbers

In the system PbF2–NdF3–SnF2 are formed solid solutions of the heterovalent substitution Pb0,86-хNdхSn1,14F4+х (0 < x ≤ 0,17) with structure of β–PbSnF4. At x > 0,17 on the X-ray diffractograms, in addition to the basic structure, additional peaks are recorded to the reflexes of the individual NdF3. For single-phase solid solutions, the calculated parameters of the crystal lattice are satisfactorily described by the Vegard rule. The introduction of ions of Nd3+ into the initial structure leads to an increase in the parameter с of the elementary cell from 51.267 Å for x = 0,03 to 51.577 Å for x = 0.17. The replacement of a part of leads ions to neodymium ions an increase in electrical conductivity compared with Pb0.86Sn1.14F4. The slight replacement (3.0 mol. %) of Pb2+ ions by Nd3+ in the structure of Pb0.86Sn1.14F4 causes an increase in the electrical conductivity at T> 530 K (6.88·10-2 S/cm compared to 2.41·10-2 S/cm for the initial sample compound Pb0.86Sn1.14F4). In the region of lower temperatures, the electrical conductivity of the samples of this composition decreases, and below that temperature, on the contrary, slightly reduces the electrical conductivity, approaching the values characteristic of β-PbSnF4. The activation energy of the conductivity thus increases over the entire temperature range. A further increase in the concentration of Nd3+ ions in the synthesized samples causes an increase in their fluoride-ion conductivity throughout the temperature range. It should be noted that samples with a content of 10-15 mol% NdF3 at T>500 K have comparable conductivity values. At lower temperatures, the higher the conductivity, the higher the concentration of the substituent. The highest conductivity and the lowest activation energy have the sample Pb0.69Nd0.17Sn1.14F4.17 (σ373=3.68·10-2 S/сm, Ea=0,1 eV). The fluorine anions in synthesized phases are in three structurally-equivalent positions. The charge transfer is provided by the highly mobile interstitial fluorine anions, whose concentration increases with increasing temperature and concentration of NdF3. The transfer numbers for fluorine anions are not less than 0.99, practically independent of the concentration of neodymium trifluoride.

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