Electrical Resistivity Anomalies in SbxVyMozOt Phases

2011 ◽  
Vol 170 ◽  
pp. 5-8 ◽  
Author(s):  
Tadeusz Groń ◽  
E. Filipek ◽  
Henryk Duda ◽  
S. Mazur ◽  
K. Bärner
Keyword(s):  
Electrical Resistivity ◽  
General Formula ◽  
Solid Solutions ◽  
Type Conductivity ◽  
Temperature Range ◽  
Small Polarons

Electrical resistivity dips in the temperature range 269-287 K and n-type conductivity below 415 K for solid solutions of MoO3 in SbVO5 with general formula SbxVyMozOt are observed. The electrical resistivity anomalies are interpreted as due to conduction of small-polarons, generated here as electrons together with distortions of their associated defective oxygen lattice and/or alternatively based on the crossover of electronic or polaronic states.

scholarly journals Electrical Characterization of La2-xSrxCuO4-y Superconductors

1989 ◽  
Vol 44 (1) ◽  
pp. 26-28 ◽  
Author(s):  
G. Chiodelli ◽  
G. Campari-Viganò ◽  
V. Massarotti ◽  
G. Flor
Keyword(s):  
Electrical Resistivity ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Solid Solutions ◽  
Electrical Characterization ◽  
Superconducting Transition ◽  
Electrical Behaviour ◽  
Temperature Range

Abstract The electrical behaviour of La2-xSrxCuO4-y solid solutions (with x = 0, x = 0.025, x = 0.05, and x = 0.15) at temperatures between 10 and 900 K and under different oxygen partial pressure pO2 = 1 ÷ 10-6 atm) has been investigated. The samples prepared and measured under an O2 flux (i.e., with y = 0) show a superconducting transition with Tc = 46, 29. 37 K for x = 0. 0.05 and 0.15, respectively. The samples with x = 0.025, y = 0, and x = 0, y ≠ 0 exhibit no sign of superconductivity. In the temperature range 100-900 K. La2CuO4 is semiconducting, whereas the electrical resistivity is independent of temperature for the x =0.025 sample, and the x = 0.05 and x = 0.15 are metallic.

Semiconducting Molybdenum Pyrochlores for high Temperature Applications

1998 ◽  
Vol 512 ◽  
Author(s):  
V. Ponnambalam ◽  
U. V. Varadaraju
Keyword(s):  
Activation Energy ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Low Temperature ◽  
Solid Solutions ◽  
Power Factor ◽  
Charge Carriers ◽  
Temperature Range ◽  
Maximum Power Factor ◽  
Increasing Temperature

ABSTRACTThe solid solutions (Y1-xYbx)2Mo2O7 were prepared and the systematic changes in the electrical resistivity (ρ=l/σ), thermopower (S) and power factor (S2σ) have been studied in the temperature range 300–900 K. The lattice parameters ‘a’ and ‘c’ are smaller for higher Yb3+ content phases due to smaller Yb3+ radius and a small tetragonality is observed for all the phases. Semiconducting behaviour is seen for all compositions with systematic increase in activation energy with increasing Yb content. All compositions show negative thermopower indicating electrons are the majority charge carriers in the temperature range of measurements. The calculated power factor values S2σ increase with increasing temperature in the low temperature region and a maximum power factor of ∼0.76×10−7 Wcm−1K−2 is observed at 650K.

scholarly journals Кинетические свойства твердых растворов Mn-=SUB=-1-x-=/SUB=-Gd-=SUB=-x-=/SUB=-Se

2018 ◽  
Vol 60 (9) ◽  
pp. 1650
Author(s):  
О.Б. Романова ◽  
С.С. Аплеснин ◽  
А.М. Харьков ◽  
В.В. Кретинин ◽  
А.М. Живулько
Keyword(s):  
Kinetic Study ◽  
Temperature Dependence ◽  
Crystal Field ◽  
Solid Solutions ◽  
Hall Constant ◽  
Type Conductivity ◽  
Temperature Range ◽  
The Difference

AbstractThe results of kinetic study of the Mn_1 – x Gd_ x Se chalcogenide solid solutions with different substitute concentrations (0 ≤ x ≤ 0.15) in the temperature range of 80–400 K are reported. The difference between the Hall constant and thermopower signs has been found. The electron-type conductivity determined from the Hall constant and hysteresis of the I – V characteristics have been explained by the existence of nanoareas with local electric polarizations. The sharp extrema observed in the temperature dependence of thermopower are explained by splitting of a narrow 4 f subband by the crystal field.

Effects of Nb doping on thermoelectric properties of Zn4Sb3 at high temperatures

2009 ◽  
Vol 24 (2) ◽  
pp. 430-435 ◽  
Author(s):  
D. Li ◽  
H.H. Hng ◽  
J. Ma ◽  
X.Y. Qin
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
High Temperatures ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Thermoelectric Performance ◽  
Temperature Range ◽  
A Value ◽  
Nb Doping ◽  
Thermal Conductivities

The thermoelectric properties of Nb-doped Zn4Sb3 compounds, (Zn1–xNbx)4Sb3 (x = 0, 0.005, and 0.01), were investigated at temperatures ranging from 300 to 685 K. The results showed that by substituting Zn with Nb, the thermal conductivities of all the Nb-doped compounds were lower than that of the pristine β-Zn4Sb3. Among the compounds studied, the lightly substituted (Zn0.995Nb0.005)4Sb3 compound exhibited the best thermoelectric performance due to the improvement in both its electrical resistivity and thermal conductivity. Its figure of merit, ZT, was greater than the undoped Zn4Sb3 compound for the temperature range investigated. In particular, the ZT of (Zn0.995Nb0.005)4Sb3 reached a value of 1.1 at 680 K, which was 69% greater than that of the undoped Zn4Sb3 obtained in this study.

scholarly journals Isotropic Low Thermal Expansion over a Wide Temperature Range in Ti1–xZrxF3+x (0.1 ≤ x ≤ 0.5) Solid Solutions

2018 ◽  
Vol 57 (22) ◽  
pp. 14396-14400 ◽  
Author(s):  
Cheng Yang ◽  
Yugang Zhang ◽  
Jianming Bai ◽  
Peng Tong ◽  
Jianchao Lin ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Solid Solutions ◽  
Wide Temperature Range ◽  
Temperature Range ◽  
Low Thermal Expansion

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.

scholarly journals ABO4 type scheelite phases in (Ca/Sr)MoO4 - BiVO4 - Bi2Mo3O12 systems: synthesis, structure and optical properties

2021 ◽  
Vol 8 (2) ◽  
pp. 20218204
Author(s):  
Z. A. Mikhaylovskaya ◽  
E. S. Buyanova ◽  
S. A. Petrova ◽  
A. V. Klimova
Keyword(s):  
Optical Properties ◽  
Solid State ◽  
General Formula ◽  
Solid Solutions ◽  
Triple System ◽  
Complex Oxides ◽  
Vanadium Content ◽  
Energy Gaps ◽  
Munk Function ◽  
State Technique

The cation deficient complex oxides of (Ca/Sr)MoO4 - BiVO4 - Bi2Mo3O12 triple system are promising photocatalysts and pigments. Compounds with general formula of Ca1−1.5x-yBix+yФxMo1-yVyO4  and Sr1−1.5x-yBix+yФxMo1-yVyO4 were synthesized byconvention solid state technique in the range of 550–720 °C. Two wide regions of the solid solutions (ordinary and superstructured scheelite-type phases respectively) were found for each system. The diffuse scatering of homogeneous samples was investigated in the range of 190–1100 nm. Energy gaps calculated with linear approximation of Kubelka-Munk function decreases with bismuth and vanadium content.

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