Influence of Eu Substitution for Y on the High Temperature Electric Transport Properties of YBaCo4O7+δ

2013 ◽  
Vol 724-725 ◽  
pp. 1029-1032 ◽  
Author(s):  
Qing Lin He ◽  
Feng Gao ◽  
Hong Zhang Song ◽  
Xing Hu
Keyword(s):  
Activation Energy ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Transport Properties ◽  
Power Factor ◽  
Electric Resistivity ◽  
Electric Transport ◽  
Seebeck Coefficients ◽  
Higher Power ◽  
Unmodified Sample

The electric resistivity, Seebeck coefficients and power factors of Y1-xEuxBaCo4O7+δ(x = 0.0, 0.05, 0.1, 0.2) ceramics were investigated from 400K to 1000K. The results show that the presence of Eu decreases electrical resistivity, and has little effect on Seebeck coefficients of the samples. The activation energy of conductivity is calculated by the Arrhenius plots in the semiconductive region. According to power factors, the optimum Eu substitution amount is x = 0.1, which results in a higher power factor of 67.5 μWm-1K-2at 1000K, 30% higher than unmodified sample YBaCo4O7+δ.

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.

Thermoelectric Properties of Semiconducting Intermetallic Compounds: FeGa3and RuGa3

2003 ◽  
Vol 793 ◽  
Author(s):  
Y. Amagai ◽  
A. Yamamoto ◽  
C. H. Lee ◽  
H. Takazawa ◽  
T. Noguchi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Transport Properties ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
High Seebeck Coefficient

ABSTRACTWe report transport properties of polycrystalline TMGa3(TM = Fe and Ru) compounds in the temperature range 313K<T<973K. These compounds exhibit semiconductorlike behavior with relatively high Seebeck coefficient, electrical resistivity, and Hall carrier concentrations at room temperature in the range of 1017- 1018cm−3. Seebeck coefficient measurements reveal that FeGa3isn-type material, while the Seebeck coefficient of RuGa3changes signs rapidly from large positive values to large negative values around 450K. The thermal conductivity of these compounds is estimated to be 3.5Wm−1K−1at room temperature and decreased to 2.5Wm−1K−1for FeGa3and 2.0Wm−1K−1for RuGa3at high temperature. The resulting thermoelectric figure of merit,ZT, at 945K for RuGa3reaches 0.18.

High-temperature Thermoelectric Properties of the Ca1-xBixMnO3 System

2002 ◽  
Vol 17 (5) ◽  
pp. 1092-1095 ◽  
Author(s):  
Gaojie Xu ◽  
Ryoji Funahashi ◽  
Ichiro Matsubara ◽  
Masahiro Shikano ◽  
Yuqin Zhou
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Thermoelectric Power ◽  
Power Factor ◽  
X Ray Diffraction ◽  
Absolute Value ◽  
X Ray ◽  
Figures Of Merit ◽  
Bi Doping

Polycrystalline samples of Ca1-xBixMnO3 (0.02 ≤ x ≤ 0.20) were studied by means of x-ray diffraction, electrical resistivity (ρ), thermoelectric power (S), and thermal conductivity (κ) at high temperature. Bi doping leads to the lattice parameters a, b, and c increasing. And the ρ and the absolute value of S decrease rapidly with Bi doping. The largest power factor, S2/ρ, is obtained in the x = 0.04 sample, which is 3.6×10−4 Wm−1 K−2 at 400 K. The figures of merit (Z = S2/ρκ) for this sample and 1.0×10−4 and 0.86 × 10−4 K−1 at 600 and 1000 K, respectively.

High-Temperature Thermoelectric Properties of Pb- and La-Substituted Bi2Sr2Co2Oy Misfit Compounds

2010 ◽  
Vol 105-106 ◽  
pp. 336-338 ◽  
Author(s):  
Hao Shan Hao ◽  
Jin Qin Ye ◽  
Yong Tao Liu ◽  
Xing Hu
Keyword(s):  
High Temperature ◽  
Solid State ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Thermoelectric Performance ◽  
Simultaneous Increase ◽  
Reaction Method ◽  
Seebeck Coefficients

Pb- and La-substituted (Bi,Pb)2(Sr,La)2Co2Oy samples were prepared by solid-state reaction method and the effect of element substitution on the high-temperature thermoelectric properties was investigated. It was found that the presence of Pb and La elements improved the thermoelectric properties of the Bi2Sr2Co2Oy system owing to the simultaneous increase of conductivity and Seebeck coefficients. The optimal thermoelectric performance was obtained in Pb and La co-substituted samples and the power factor could reach 2.1×10-4Wm-1K-2 at 1000K.

Reassess study of high temperature electric transport properties of PbTiO3

2019 ◽  
Vol 770 ◽  
pp. 308-319 ◽  
Author(s):  
M.H. Ammar ◽  
M.M. El-hady ◽  
T.M. Salama ◽  
A.A. Bahgat
Keyword(s):  
High Temperature ◽  
Transport Properties ◽  
Electric Transport

Investigation of Preparation and Thermoelectric Properties of Ca2.5La0.5Co4O9 Porous Ceramics

2015 ◽  
Vol 1120-1121 ◽  
pp. 98-101
Author(s):  
Peng Xia Ji ◽  
Hui Min Zhang ◽  
Ai Min Chang
Keyword(s):  
Electrical Resistivity ◽  
Solid State ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Thermoelectric Materials ◽  
Solid State Reaction ◽  
Porous Ceramics ◽  
Pore Former ◽  
Higher Power

CO(NH2)2 as pore-former used to prepare porous Ca2.5La0.5Co4O9 thermoelectric materialsby solid-state reaction technique.Microstructure,density and thermoelectric properties (temperature dependence of electrical resistivity,Seebeck coefficient) of the samples were studied in details.The results have shown that the porosity increases and the pore structure is improved with the pore-former content increasing,and electrical resistivity and density decrease while Seebeck coefficient raise.The improvement in electrical resistivity and Seebeck coefficient leads to higher power factor values at 913 K (around 1.32 mW/cm·K2) than undoped samples.

Influence of Cu Doping on the Thermoelectric Properties of Bi1.5Pb0.5Sr1.8La0.2Co2Oy

2013 ◽  
Vol 423-426 ◽  
pp. 593-596
Author(s):  
Qing Lin He ◽  
Zhan Ying Guo ◽  
Xing Hu ◽  
Hong Zhang Song
Keyword(s):  
Electrical Resistivity ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Solid State Reaction Method ◽  
Electric Transport ◽  
Cu Doping ◽  
Seebeck Coefficients ◽  
Dimensionless Figure Of Merit ◽  
Element Doping ◽  
Properties Of Materials

Cu doped Bi1.5Pb0.5Sr1.8La0.2Co2-xCuxOy(x = 0.0, 0.2, 0.4) samples were prepared through the solid state reaction method. The influence of different Cu doping contents on electrical resistivity, Seebeck coefficients, thermal conductivity, and the dimensionless figure of meritZTwas investigated. All the samples of Cu concentration 0.4 are single phases. The electrical resistivity of Bi1.5Pb0.5Sr1.8La0.2Co1.8Cu0.2Oydescends, and itsZTvalues are enhanced obviously. The results show that suitable element doping can modify the electric transport properties and enhance thermoelectric properties of materials.

The Electrical Conductance of Some Alkali- and Divalent Transition Metal TCNQ Salts

1978 ◽  
Vol 33 (3) ◽  
pp. 344-346 ◽  
Author(s):  
H. H. Afify ◽  
F. M. Abdel-Kerim ◽  
H. F. Aly ◽  
A. A. Shabaka
Keyword(s):  
Phase Transition ◽  
Activation Energy ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Transition Metal ◽  
Temperature Region ◽  
Electrical Conductance ◽  
Metal Cations ◽  
High Temperature Region ◽  
Transition Metal Cations

AbstractThe electrical resistivity of the tetracyanoquinodimethane salts of ten alkali and transition metal cations has been investigated at temperatures from 300 to 470 K. The measurements indicate a phase transition, the activation energy of conductance being smaller in the high temperature region. The nature of this phase transition is discussed.

SYNTHESIS AND ELECTRICAL RESISTIVITY OF NICKEL POLYMETHACRYLATE

1992 ◽  
Vol 06 (10) ◽  
pp. 581-586 ◽  
Author(s):  
M. H. CHOHAN ◽  
A. H. KHALID ◽  
M. ZULFIQAR ◽  
P. K. BUTT ◽  
FARAH KHAN ◽  
...  
Keyword(s):  
Activation Energy ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Sodium Hydroxide ◽  
Low Temperatures ◽  
Room Temperature ◽  
Polymethacrylic Acid

Synthesis of nickel polymethacrylate was carried out using methanolic solutions of sodium hydroxide and polymethacrylic acid. The electrical resistivity of the pellets made from Ni-polymethacrylate was measured at different voltages and temperatures. Results showed that the electrical resistivity of Ni-polymethacrylate decreases significantly with voltage in high temperature regions but the decrease is insignificant at temperatures nearing room temperature. The activation energy at low temperatures is approximately 0.8 eV whereas at high temperature it is in the range 0.21–0.27 eV.

Study of the percolative nature of thermoelectric power and resistivity in Pr0.66R0.04Sr0.3MnO3 (R = Tb, Y, Ho and Er) manganites.

2004 ◽  
Vol 848 ◽  
Author(s):  
N. Rama ◽  
V. Sankaranarayanan ◽  
M.S.R. Rao
Keyword(s):  
Activation Energy ◽  
High Temperature ◽  
Curie Temperature ◽  
Transport Properties ◽  
Thermoelectric Power ◽  
Strong Dependence ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Resistivity Data ◽  
Temperature Activation

ABSTRACTWe have studied the resistivity and thermoelectric power of Pr0.66R0.04Sr0.3MnO3 where R = Tb, Y, Ho and Er and have analyzed it within a percolative framework. Both resistivity and thermoelectric power quantities were found to show a strong dependence on the disorder (<σ>2) with the high temperature activation energy in both increasing as <σ>2 is increased, implying that as the disorder increases, carriers get more localized. The percolative nature of the thermopower was analyzed assuming that the lattice has coexisting metallic (Smet) and insulating (Sins) components above and below the Curie temperature (TC) which are independent of each other. Hence total S(T) = pSmet(T) + (1-p)Sins with the volume metallic fraction p=1/(1+exp(-Uo(1-T/TC)/kBT) [1]. A similar analysis was done using the resistivity data. It was seen that the TC from both thermopower and resistivity fits were nearly the same indicating that they have a common origin. This analysis clearly proves that the metal insulator transition in manganites is percolative in nature and that the transport properties show a strong percolation tendency.

Sign in / Sign up

Export Citation Format

Share Document