Thermoelectric Properties of Cd3−xAxTeO6 (A = In3+, La3+ and Bi3+) Ceramics

2001 ◽  
Vol 691 ◽  
Author(s):  
Weiling Luan ◽  
Yue Jin Shan ◽  
Mitsuru Itoh ◽  
Hideo Imoto
Keyword(s):  
Seebeck Coefficient ◽  
Temperature Dependence ◽  
Oxygen Vacancies ◽  
Negative Temperature ◽  
Charge Carriers ◽  
Perovskite Oxide ◽  
Thermoelectric Power Factor ◽  
Metallic Behavior ◽  
Seebeck Coefficients ◽  
Trivalent Cations

ABSTRACTPerovskite oxide Cd3TeO6 was electron-doped by the introduction of oxygen vacancies and substitution of trivalent cations, In3+, La3+ and Bi3+. Their electric properties were investigated and compared with that of undoped Cd3TeO6. Negative temperature dependence of resistivity was observed in undoped, air-sintered Cd3TeO6. The resis tivity of Cd3−xAxTeO6 (A = In3+, La3+ and Bi3+) showed a metallic behavior with very slight temperature dependence. Indium-doped samples gave a low resistivity, which were decreased by more than three orders of magnitudes than that of air-sintered, undoped Cd3TeO6. The negative Seebeck coefficient and Hall coefficient obtained from all samples indicate that electrons are the charge carriers. The absolute Seebeck coefficients values of doped samples are decreased by 5 ∼ 10 times than that observed in undoped Cd3TeO6. Fortunately, the resistivity of indium-doped samples is low enough to provide a good thermoelectric power factor, and the optimum value of Cd2.97In0.03TeO6 was calculated as 1.35×10−4 Wm−1K−2. This result is close to that of the current best n-type perovskite thermoelectric material Ba0.4Sr0.6PbO3.

Influence of Doping Concentration and Ambient Temperature on the Cross-Plane Seebeck Coefficient of InGaAs/InAlAs superlattices

2003 ◽  
Vol 793 ◽  
Author(s):  
Yan Zhang ◽  
Daryoosh Vashaee ◽  
Rajeev Singh ◽  
Ali Shakouri ◽  
Gehong Zeng ◽  
...  
Keyword(s):  
Seebeck Coefficient ◽  
Figure Of Merit ◽  
Doping Concentration ◽  
Molecular Beam ◽  
Bulk Material ◽  
Promising Candidate ◽  
Thermoelectric Power Factor ◽  
Seebeck Coefficients ◽  
Chip Temperature ◽  
On Chip

ABSTRACTWe have developed thin film heaters/sensors that can be integrated on top of superlattice microcoolers to measure the Seebeck coefficient perpendicular to the layer. In this paper, we discuss the Seebeck coefficients of InGaAs/InAlAs superlattices grown with Molecular Beam Epitaxy (MBE) that have different doping concentrations, varying between 2e18, 4e18, and 8e18 to 3e19 cm−3. It was interesting to find out that – contrary to the behavior in bulk material – the Seebeck coefficient did not decrease monotonically with doping concentration. A preliminary theory of thermoelectric transport in superlattices in the regime of miniband formation has been developed to fit the experimental results. The miniband formation could enhance the thermoelectric power factor (Seebeck coefficient square times electrical conductivity) and thereby improve the Figure of merit, ZT. With this improvement, InGaAs/InAlAs superlattice microcooler become a promising candidate for on-chip temperature control.

GROWTH AND ANISOTROPIC RESISTIVITY OF Bi2Sr2CaCu2Oy SINGLE CRYSTALS WITH ZERO RESISTIVITY AT 90 K

1990 ◽  
Vol 04 (18) ◽  
pp. 1153-1161
Author(s):  
G. YANG ◽  
Z.X. ZHAO
Keyword(s):  
Data Analysis ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Linear Relation ◽  
Negative Temperature ◽  
Oxide Superconductors ◽  
Superconducting Transition ◽  
Flux Method ◽  
Metallic Behavior ◽  
X Ray

A Bi2Sr2CaCu2Oy single crystal with zero resistivity at 90 K was grown by self-flux method. The diffraction of TEM and X-ray showed that the crystals were in “2212” phase with c=3.07 nm. Diamagnetism appeared at 91.5 K. The anisotropic resistivity of the crystal has been measured using the Montgomery technique. The superconducting transition onset in resistivity occurred at about 95 K and zero resistivity at 90 K. The resistivity showed strong anisotropic characteristics, with typical metallic behavior above 122 K and a semiconducting-like temperature dependence before superconducting transition in the a-b plane, which is quite different from previous results. The resistivity in the c-direction showed semiconducting-like temperature dependence, like other high Tc oxide superconductors but only above 122 K. ρcT versus T2 could be quite well represented by a linear relation. At present, it is difficult to determine the temperature dependence of resistivity in-plane from data analysis. The structure instability may be responsible for the negative temperature dependence of resistivity below 122 K.

scholarly journals A potential approach to enhance the Seebeck coefficient of UHMWPE by using the graphene oxide

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Aqsa Irfan ◽  
Malik Naqash Mehmood ◽  
Malik Sajjad Mehmood ◽  
Arif Aziz ◽  
Mansoor Ahmad Baluch ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Seebeck Coefficient ◽  
Figure Of Merit ◽  
Charge Carriers ◽  
Potential Candidate ◽  
Conductive Network ◽  
Mechanical Mixing ◽  
Seebeck Coefficients ◽  
Thermal Insulating ◽  
Ultra High Molecular Weight

Thermoelectric materials have been the competent source for the production of energy in present decades. The most important and potential parameter required for material to have beter thermoelectric characteristics is the Seebeck coefficient. In this work, ultra high molecular weight polyethylene (UHMWPE) and graphene oxide (GO) nanocomposites was prepared with mechanical mixing by containing 10000ppm, 50000ppm, 70000ppm, 100000ppm, 150000ppm, and 200000ppm loadings of graphene oxide.  Due to intrinsic insulating nature of UHMWPE, the value of Seebeck for pristine UHMWPE and its nanocomposites with 10000ppm, & 50000ppm of GO concentration was too low to be detected. However, the Seebeck coefficient for composites with 70000ppm, 100000ppm, 150000ppm, and 200000ppm loadings of GO was found to be 180, 206, 230 and 235 µV/K, respectively. These higher values of Seebeck coefficients were attributed to superior thermal insulating nature of UHMWPE and conductive network induced by the GO within the UHMWPE insulating matrix. Although, values of figure of merit and power factor were negligibly small due to lower concentration of charge carriers in UHMWPE/GO nanocomposites but still reported results are extremely hopeful for considering the composite as the potential candidate for thermoelectric applications. 

scholarly journals Computational study on the mechanism and kinetics for the reaction between HO2 and n-propyl peroxy radical

RSC Advances ◽  
2019 ◽  
Vol 9 (69) ◽  
pp. 40437-40444
Author(s):  
Zhenli Yang ◽  
Xiaoxiao Lin ◽  
Jiacheng Zhou ◽  
Mingfeng Hu ◽  
Yanbo Gai ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Temperature Regime ◽  
Computational Study ◽  
Peroxy Radical ◽  
Negative Temperature ◽  
Mechanism And Kinetics ◽  
Lower Temperature

The negative temperature dependence for the HO2 + n-C3H7O2 reaction in lower temperature regime.

DIELECTRIC CONSTANT AND SEEBECK COEFFICIENT FOR SEMICONDUCTORS: THERMODYNAMIC AND DFT STUDIES

2013 ◽  
Vol 12 (06) ◽  
pp. 1350057 ◽  
Author(s):  
HSIU-YA TASI ◽  
CHAOYUAN ZHU
Keyword(s):  
Boundary Condition ◽  
Dielectric Constant ◽  
Seebeck Coefficient ◽  
Gas Phase ◽  
Present Method ◽  
Dielectric Constants ◽  
Semiconductor Materials ◽  
Electronic Polarizability ◽  
Seebeck Coefficients ◽  
Good Agreement

Dielectric constants and Seebeck coefficients for semiconductor materials are studied by thermodynamic method plus ab initio quantum density functional theory (DFT). A single molecule which is formed in semiconductor material is treated in gas phase with molecular boundary condition and then electronic polarizability is directly calculated through Mulliken and atomic polar tensor (APT) density charges in the presence of the external electric field. This electronic polarizability can be converted to dielectric constant for solid material through the Clausius–Mossotti formula. Seebeck coefficient is first simulated in gas phase by thermodynamic method and then its value divided by its dielectric constant is regarded as Seebeck coefficient for solid materials. Furthermore, unit cell of semiconductor material is calculated with periodic boundary condition and its solid structure properties such as lattice constant and band gap are obtained. In this way, proper DFT function and basis set are selected to simulate electronic polarizability directly and Seebeck coefficient through chemical potential. Three semiconductor materials Mg 2 Si , β- FeSi 2 and SiGe are extensively tested by DFT method with B3LYP, BLYP and M05 functionals, and dielectric constants simulated by the present method are in good agreement with experimental values. Seebeck coefficients simulated by the present method are in reasonable good agreement with experiments and temperature dependence of Seebeck coefficients basically follows experimental results as well. The present method works much better than the conventional energy band structure theory for Seebeck coefficients of three semiconductors mentioned above. Simulation with periodic boundary condition can be generalized directly to treat with doped semiconductor in near future.

Negative Temperature-Dependence of Stress-Induced R→B19′ Transformation in Nanocrystalline NiTi Alloy

2021 ◽  
Author(s):  
Taotao Wang ◽  
Xiangxiang Rao ◽  
Daqiang Jiang ◽  
Yang Ren ◽  
Lishan Cui ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Niti Alloy ◽  
Negative Temperature

scholarly journals Identification of a positive-Seebeck-coefficient exohedral fullerene

Nanoscale ◽  
2016 ◽  
Vol 8 (28) ◽  
pp. 13597-13602 ◽  
Author(s):  
Nasser Almutlaq ◽  
Qusiy Al-Galiby ◽  
Steven Bailey ◽  
Colin J. Lambert
Keyword(s):  
Seebeck Coefficient ◽  
Seebeck Coefficients

If fullerene-based thermoelectricity is to become a viable technology, then fullerenes exhibiting both positive and negative Seebeck coefficients are needed.

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