The temperature dependence of the activation energy of the electrical conductivity of sea water in the temperature range 0°C to 10°C

1964 ◽  
Vol 69 (6) ◽  
pp. 1152-1154 ◽  
Author(s):  
R. A. Horne ◽  
R. A. Courant
2019 ◽  
Vol 85 (5) ◽  
pp. 60-68
Author(s):  
Yuliay Pogorenko ◽  
Anatoliy Omel’chuk ◽  
Roman Pshenichny ◽  
Anton Nagornyi

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.


2019 ◽  
Vol 61 (7) ◽  
pp. 1270
Author(s):  
А.В. Яценко ◽  
С.В. Евдокимов ◽  
М.Н. Палатников ◽  
Н.В. Сидоров

The temperature dependence of the electrical conductivity and the primary pyroelectric coefficient of lithium niobate crystals LiNbO3 grown from a melt with K2O flux was investigated in the range of 292–450 K . It is shown that these crystals are characterized by a strong anisotropy of electrical conductivity, and in the temperature range studied, proton conductivity dominates.


2013 ◽  
Vol 22 ◽  
pp. 255-260 ◽  
Author(s):  
R. V. BARDE ◽  
S. A. WAGHULEY

The binary glassy systems 60V2O5-(40-x)P2O5 –xB2O3 were prepared by melt quenching technique. The mole of B2O3 was varies from 5 to 20 mol % with constant mol % of V2O5 during preparation of glass samples. The dc electrical conductivity of samples was measured in temperature range 303-473 K and found to be higher for sample 60 V2O5-20P2O5 –20B2O3 . Using the Arrhenius equation of conductivity, the activation energy of conduction is estimated. The conduction in these glasses is takes place by phonon-assisted hopping between the localized states.


2016 ◽  
Vol 30 (04) ◽  
pp. 1650034 ◽  
Author(s):  
S. V. Savich ◽  
A. V. Samoilov ◽  
R. V. Vovk ◽  
O. V. Dobrovolskiy ◽  
S. N. Kamchatna ◽  
...  

The electrical conductivity of hafnium (Hf)-doped YBa2Cu3O[Formula: see text] ceramics is investigated. Hf doping has been revealed to lead to an increase of the number of effective scattering centers for the normal charge carriers. In a broad temperature range, the excess conductivity of the investigated samples obeys an exponential temperature dependence, while near [Formula: see text] it is satisfactorily described by the Aslamazov–Larkin model. Meanwhile, Hf doping has been shown to lead to a notable broadening of the temperature range for the manifestation of the pseudogap anomaly in the [Formula: see text]-plane.


2015 ◽  
Vol 230 ◽  
pp. 233-237 ◽  
Author(s):  
Aleksandr V. Yatsenko ◽  
A.S. Pritulenko ◽  
S.V. Yevdokimov ◽  
Dmytro Yu. Sugak ◽  
I.I. Syvorotka ◽  
...  

The temperature dependence of the dark electrical conductivity of the LiNbO3(LN) crystals annealed in saturated H2O and D2O vapor in the range 293...400 K is investigated. It is found that the activation energy of the electrical conductivity is equal to (0.71 ± 0.02) eV and is close this value of LN samples, reduced in hydrogen. Annealing in ampoules with H2O vapor also lead to LN optical spectra changes such annealing in H2. The nature of this phenomenon is discussed.


2004 ◽  
Vol 11 (04n05) ◽  
pp. 443-446
Author(s):  
P. H. SONI ◽  
C. F. DESAI ◽  
S. R. BHAVSAR

Temperature dependence of the Vickers microhardness of Sn 0.2 Bi 1.8 Te 3 single crystals has been studied. Loading time dependence of microhardness at different temperatures has been used for creep study in the temperature range 303 K–373 K. The activation energy for indentation creep of the crystals has been evaluated.


2020 ◽  
Vol 86 (5) ◽  
pp. 24-37
Author(s):  
Pohorenko Yuliia ◽  
Omel’chuk Anatoliy ◽  
Nagornyi Anton

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.


2003 ◽  
Vol 217 (6) ◽  
pp. 667-676 ◽  
Author(s):  
F. M. Ismail ◽  
F. F. Hamad ◽  
H. S. Faraj

AbstractThe a.c. conductivity as a function of temperature was measured for ten prepared samples. The measurements were carried out in the temperature range 25–340°C. The sample CuMn2O4 prepared either from oxide or carbonate contains the least impurity content, while the sample Cu1.5Mn1.5O4 from oxide origin and Cu1.6Mn1.4O4 from carbonate origin contain the highest impurity content. The activation energy ΔE1 values for the oxide origin samples are nearly the same of those obtained from carbonate origin. The variation of ΔE2 values with concentration of copper content (x) appears to be consistent.


2012 ◽  
Vol 323-325 ◽  
pp. 171-176 ◽  
Author(s):  
D. Prokoshkina ◽  
A.O. Rodin ◽  
V. Esin

The temperature dependence of the bulk diffusion coefficient of Fe in Cu is determined by EDX in the temperature range from 923 to 1273 K, , m2/s. These results are different from that obtained earlier by radiotracer technique: activation energy is less by 30 kJ/mol and pre-exponential factor is 50 times smaller. Deviations from ideality of investigated solutions do not explain the differences; consequently, the thermodynamical factor would not responsible for such an effect. Fast grain boundary diffusion of Fe in Cu was not observed in the temperature range from 823 to 1073 K.


1997 ◽  
Vol 52 (8-9) ◽  
pp. 621-628 ◽  
Author(s):  
W. Osak

Abstract Charging currents, J-V characteristics and electron conductivity have been measured in triglycine sulphate along three crystallographic directions: a, b and c. The measurements have been taken in a wide temperature range between −196°C and 80 °C. It is found that the charging currents have short relaxation times in the directions: a and c and a long relaxation time along the ferroelec-tric b axis. The J-V characteristics in the direction of the a and c axes have the shapes characteristic for linear dielectrics with space charge limited currents. The J-V characteristic for the b axis depends on the temperature: In the region of the phase transition the Fridkin-Kreher formula (J ∝ V4/3) is satisfied; for low temperatures characteristic agrees with SCLC theory for linear dielectrics with Gaussian traps energy distribution. The d.c. conductivity along the c axis is much higher than along the a and b axes. In the investigated temperature range, the electrical conductivity has an activation character. For −100 °C < T < −193 °C there is: σ ∝ (1/T) exp (− E/kT) . The activation energy depends both on the crystallographic direction and on the temperature-range. For low temperatures, T < −100 °C, the activation energies are very small (of the order of a few hundreds eV).


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