Showing papers on "Seebeck coefficient published in 1978"
TL;DR: The phase analysis for the system (l−x) CrSi2 + xMnSi2 in the range 0.5 by X-ray technique was carried out in this paper.
113 citations
TL;DR: In this paper, the electrical resistivity, thermal conductivity, and the thermoelectric power were measured on the anomalous CeCu2Si2 compound and on the reference compound, and it was shown that resistivity and temperature dependences were in accord with those found in otherd band metals.
Abstract: We report measurements of the electrical resistivityρ, the thermal conductivityk and the thermoelectric powerS between 1.5K and 300K on the anomalous CeCu2Si2 compound and on LaCu2Si2 as reference compound. For LaCu2Si2 the temperature dependences ofρ andS are in accord with those found in otherd band metals. For CeCu2Si2 the observed resistivity (ρ≃220 µΩ cm at 200K) leads to a very short electronic mean free path which is of the order of the Ce-Ce spacing. Correspondingly,k is almost identical with the phonon contributionk
p
. Below 20K, resistivity and thermoelectric power strongly suggest Fermi liquid behavior with a “degeneracy temperature” between 20K and 40K. Above 200K, bothρ andS decrease proportionally to −ln(T/1 K).
77 citations
TL;DR: In this article, electrical conductivity was investigated in polycrystalline lead zirconate-titanate ceramics, with and without various dopants and stoichiometry, fabricated from chemical solutions and mixed-oxide powders.
Abstract: Electrical conductivity was investigated in polycrystalline lead zirconate-titanate ceramics, with and without various dopants and stoichiometry, fabricated from chemical solutions and mixed-oxide powders. A multiphase packing-powder technique was used to control the stoichiometry of the system during sintering. The dc resistivity was measured by using a guard-ring method. Electrical conduction follows typical semiconductor behavior. Thermoelectric power measurements showed that hole conduction was dominant. Impurity ions which can serve as acceptors or donors significantly affect the conduction process. For undoped PZT the activation energy was 3.6 eV from 650° to 800°C and 1.4 eV at <650°C.
64 citations
TL;DR: In this paper, the anomalous temperature dependence of the resistivity in metallic glasses has been investigated using a generalized Ziman theory, a model based on Mott $s\ensuremath{-d$ scattering, and a Kondo or tunneling mechanism.
Abstract: Several theories have attempted to explain the anomalous temperature dependence of the resistivity in metallic glasses including a generalized Ziman theory, a model based on Mott $s\ensuremath{-}d$ scattering, and a model based on a Kondo or tunneling mechanism. The thermoelectric power as well as the resistivity of a glass has been measured up to the crystallization temperature and was linear over the entire region. This behavior is only consistent with the Ziman theory.
60 citations
TL;DR: In this article, a technique for the calculation of the thermoelectric power in many-particle systems exhibiting hopping conduction is presented, which provides very useful information about the microscopic nature of the ion hopping process in solid electrolytes.
57 citations
TL;DR: In this paper, both experimental and theoretical studies of electron mobility, thermoelectric power, longitudinal Nernst-Ettingshausen effect and Lorentz number in HgSe are presented.
53 citations
TL;DR: In this article, the authors studied bismuth polycrystalline films evaporated onto substrates of Corning 7059 glass to thickness d of 200-3000 A. From the data obtained, the concentrations of electrons (n) and of holes (p) as well as their mobilities μn and μp were determined without assuming that n = p.
40 citations
TL;DR: In this paper, the resistivity and seebeck coefficient of copper ferrites were measured in the temperature range between 20°C and 900°C, where the cations initiate migration.
Abstract: Resistivity and Seebeck coefficient of copper ferrites Cu1-δFe2+δO4 (0<δ<0.5) were measured in the temperature range between 20°C and 900°C. Marked changes were observed at 360°C where the cations initiate migration. Effects of metallic ratio and heat-treatment on the semiconductive properties were examined at room temperature. The sign reversal of the seebeck coefficient and the abrupt changes in resistivity took place at the tetragonality (c/a)-1=0.050 as well as at the metallic ratio δ=0.28. The observed results have been adequately interpreted in terms of the cation distribution on tetrahedral and octahedral sites. The conduction mechanism is discussed along with the cation destribution.
40 citations
TL;DR: In this article, a study of the temperature dependences reveals that the conductivity occurs by holes in a 3 d -band (Mn 3+ ) and that the mobility of the holes is not thermally activated.
38 citations
TL;DR: A method of measuring thermoelectric power of solids as a function of pressure up to nearly 10 GPa is described.
Abstract: A method of measuring thermoelectric power of solids as a function of pressure up to nearly 10 GPa is described. A tungsten carbide opposed anvil setup is used to generate the pressure.
34 citations
TL;DR: In this paper, the electrical resistivities, rho, of liquid La, Ce, Eu, Gd and Yb have been calculated on the basis of the t matrix formulation of the Ziman nearly-free electron formula.
Abstract: The electrical resistivities, rho , of liquid La, Ce, Eu, Gd and Yb have been calculated on the basis of the t matrix formulation of the Ziman nearly-free electron formula. Experimental liquid structure factors at different temperatures have been used for calculating the variation of rho with temperature. The calculated values of rho , its temperature coefficient, and the thermoelectric power for all metals show good agreement with the available experimental data. The authors interpret the observed high values of rho in terms of large p and d phase shifts and the negative temperature coefficient of rho for Eu as due to the proximity of the Fermi momentum to the position of the first peak of its structure factor.
TL;DR: In this paper, a p-type semiconductors with high mobility and thermoelectric power were found to form at about 350°C and conformed to MnTe structures.
Abstract: Vacuum deposited films formed at about 350°C conformed to MnTe structures and were p-type semiconductors. Mobility and thermoelectric power showed peaks around 315 K and their variations with temperatures suggested the predominance of ionised impurity scattering and piezoelectric scattering mechanisms respectively below and above that temperature.
TL;DR: In this article, the thermoelectric power and transverse Nernst-Ettingshausen coefficient of cadmium arsenide at room temperature have been calculated as a function of electron concentration, taking into account the HgTe-type inverted electronic energy-band structure of this material.
Abstract: The thermoelectric power and the transverse Nernst-Ettingshausen coefficient of cadmium arsenide (${\mathrm{Cd}}_{3}$${\mathrm{As}}_{2}$) at room temperature have been calculated as a function of electron concentration, taking into account the HgTe-type inverted electronic-energy-band structure of this material. In the calculation, electron scattering due to polar-optical phonons, charged centers, and acoustical phonons has been considered. Since numerical values were available for every parameter involved except ${E}_{d}$, the acoustical-deformation-potential constant, the latter was treated as an adjustable parameter to fit the theoretical curves with experimental results. It was found that ${E}_{d}$ lies between 10 and 20 eV consistent with the approximate value estimated in a previous paper.
TL;DR: The thermoelectric power in different compositions of WO3-P2O5, V2O-5-P 2O5 and MoO3 P 2O 5 has been measured in the temperature range 150 to 400K for tungsten and vanadium phosphate glasses and 300 to 450K for molybdenum glasses as mentioned in this paper.
Abstract: The thermoelectric power in different compositions of WO3-P2O5, V2O5-P2O5 and MoO3-P2O5 has been measured in the temperature range 150 to 400K for tungsten and vanadium phosphate glasses and 300 to 450K for molybdenum glasses. Heikes' formula for the thermal power and the small polaron model can adequately explain the experimental results in tungsten and vanadium phosphate glasses. However, the contribution of alpha (heat of transport associated with kinetic energy) in Heikes' formula cannot be ignored. Molybdenum phosphate glasses give an extremely low value of thermal power ( approximately 10 mu V K-1) and the measured values cannot be explained by Heikes' formula.
TL;DR: In this article, the resistivity, susceptibility, and thermopower of singlecrystal MnSb, CoSb and NiSb are presented as functions of excess metal concentration, and it is argued that the excess metal enters the structure as a neutral interstitial.
Abstract: The resistivity, susceptibility, and thermopower of single‐crystal MnSb, CoSb and NiSb are presented as functions of excess metal concentration. From these results, we propose that the electronic structure of the compounds may be described by metal 3d bands overlapping broader Sb p bands with the Fermi level lying near the top of the d bands in CoSb and above the d bands in NiSb. It is argued that the excess metal enters the structure as a neutral interstitial.
TL;DR: In this paper, the electrical conductivity and thermoelectric power of KTaO3 were measured from 900° to 1300°C over a range of oxygen partial pressures, and the calculated conductivity agreed extremely well with the experimental data over the full temperature and oxygen partial pressure range.
Abstract: The electrical conductivity and thermoelectric power of KTaO3 were measured from 900° to 1300°C over a range of oxygen partial pressures. The isothermal electrical conductivity showed a minimum at an oxygen partial pressure corresponding to the transition between p-type and n-type behavior. A point defect model was developed which involved fully ionized potassium and tantalum vacancies, singly and doubly ionized oxygen vacancies, holes, and electrons. The values of all pertinent equilibrium constants were calculated from the experimental data and the nonsimplified neutrality condition was solved to give each of the defect concentrations as a function of temperature and oxygen partial pressure. The calculated conductivity agreed extremely well with the experimental data over the full temperature and oxygen partial pressure range, and the band gap derived from these calculations (3.43 eV) was in excellent agreement with the reported value (3.5 eV).
TL;DR: In this article, the diffusion thermoelectric power of bismuth in a magnetic field is calculated assuming a two-band model with parabolic dispersion for the holes and either parabolic or non-parabolic dispersive for the electrons, and the scattering is described by a relaxation time which is either dependent on energy as for intravalley acoustic scattering or independent of energy.
Abstract: The diffusion thermoelectric power of bismuth in a magnetic field is calculated assuming a two-band model with parabolic dispersion for the holes and either parabolic or non-parabolic dispersion for the electrons. The scattering is described by a relaxation time which is assumed to be either dependent on energy as for intravalley acoustic scattering or independent of energy. Below 80K the density of charge carriers is only weakly temperature dependent and the Bethe-Sommerfeld expansion is used to derive expressions for the weak-field thermomagnetic coefficients. Above 80K a re-evaluation of earlier mobility data is performed to take into account the thermal smearing of the Fermi surfaces, and numerical integrations of the transport integrals are used. The results give a good agreement with experimental data, but this agreement is not compatible with the existence of an energy gap in the electron spectrum, such as is found in magneto-reflection experiments.
TL;DR: The absolute thermoelectric power of amorphous liquid metals has been measured in the temperature range from 300 to 1000 K as mentioned in this paper, showing no structure at either the crystallization temperature (approximately 620 K) or the glass temperature (about 714 K).
Abstract: The absolute thermoelectric power ($S$) for amorphous ${\mathrm{Fe}}_{80}$${\mathrm{B}}_{20}$ has been measured in the temperature range from 300 to 1000 K. $S$ is nearly independent of temperature in this range and, in contrast to the electrical resistivity, shows no structure at either the crystallization temperature (\ensuremath{\sim} 620 K) or the glass temperature (\ensuremath{\sim} 714 K). These results can be understood in terms of the Evans, Greenwood, and Lloyd modification of the Ziman theory for liquid metals.
TL;DR: In this article, the temperature dependence of the magnetic thermopower of Ni-Fe alloys with low Ni-concentration has been interpreted, with reasonable fitting parameters, in terms of Kasuya's relation based upon the s-d exchange interaction model.
Abstract: The thermoelectric powers of Ni–Fe alloys containing 30∼50 at.%Ni and pure Ni have been measured from 77 K to the Curie temperature as a function of the external magnetic field. The temperature dependence of the magnetic thermopower of the alloys with low Ni-concentration has been interpreted, with reasonable fitting parameters, in terms of Kasuya's relation based upon the s-d exchange interaction model. A remarkable decrease in the thermopower due to the magnetic field was observed in the alloys over a wide temperature range. This magnetic field effect has been discussed from Kasuya's relation.
TL;DR: In this article, the metal-nonmetal transition in liquid alloys such as Cs1-xAux and Li 1-xPbx is explained as resulting from concentration dependent electron charge transfer causing short-range atomic order and a change from metallic to ionic bonds.
Abstract: The metal-nonmetal transition in liquid alloys such as Cs1-xAux and Li1-xPbx is explained as resulting from concentration dependent electron charge transfer causing short-range atomic order and a change from metallic to ionic bonds. Numerical results for the electronic density of states, the electron charge transfer, the free energy of mixing, the volume change, the electrical conductivity and the thermoelectric power are given.
TL;DR: In this article, the surface microstructure was observed under an interference contrast microscope and a Michelson interference microscope and it was found that the (111) face of FeCr2S4 single crystal was covered with a group of steps 7.6± 0.7 A high.
Abstract: Chalcogenide spinel single crystals such as FeCr2S4, CoCr2S4 and some mixed crystals were grown by the chemical vapour deposition method with CrCl3 as a transport agent. The surface microstructure was observed under an interference contrast microscope and a Michelson interference microscope. It was found that the (111) face of FeCr2S4 single crystal was covered with a group of steps 7.6±0.7 A high. This is a half-elementary step in the direction. This gives an evidence that the crystals has grown by the spiral growth mechanism by Burton-Cabrera-Frank theory. Resistivity, Hall effect and thermoelectric power were measured with p-type FeCr2S4 and n-type FeCr2S4 substituted by Cu and an energy level scheme for crystalline FeCr2S4 was proposed. Between the conduction band and the valence band, from lower to higher, there exist Fe2+-band, Cr2+-level and S-valence level.
TL;DR: The thermoelectric power S(T) of MnAs1-xPx compounds has been measured in the temperature range from 5K to 350K and for compositions between x=0 and x = 0.1.
Abstract: The thermoelectric power S(T) of MnAs1-xPx compounds has been measured in the temperature range from 5K to 350K and for compositions between x=0 and x=0.1. In addition to diffusion thermopower several anomalies are observed. Phonon drag effects may be responsible for a maximum below 30K while other anomalies are related to magnetic phase transitions or to particular scattering mechanisms which have been inferred from resistivity measurements.
TL;DR: In this paper, a modified Bridgman method is described, which makes it possible to prepare homogeneous BiTeI crystals using excess iodine, where Te atoms are replaced with I atoms, which gives rise to electric conductivity.
Abstract: A modified Bridgman method is described, which makes it possible to prepare homogeneous BiTeI crystals using excess iodine. At room temperature the values of the electrical conductivity of the crystals range around 2000 Ω−1 cm−1, the Hall constant value about 0·09 cm−3 coul−1, the Seebeck coefficient about 50 μV K−1. In connection with the assumption of super-stoichiometric iodine content we expect there exist point defects in the crystals, where Te atoms are replaced with I atoms, which gives rise to electric conductivity. On the basis of the temperature dependence of the electron mobility one can suppose a mixed mechanism of the scattering of the free carriers by the acoustic branch of lattice vibrations and by ionized impurities.
TL;DR: In this paper, the thermoelectric power of NbSe 3 was measured and the type of the major carrier was estimated by comparing the results with the Hall coefficient measured by Ong and Monceau.
Abstract: The thermoelectric power of NbSe 3 was measured. The type of the major carrier is estimated by comparing the results with the Hall coefficient measured by Ong and Monceau.
TL;DR: In this article, the ionic thermoelectric power of a superionic conductor is calculated using a lattice gas model in one dimension for the case where the lattice sites are 50% occupied.
Abstract: The ionic thermoelectric power of a superionic conductor is calculated using a lattice gas model in one dimension for the case where the lattice sites are 50% occupied. The calculated thermoelectric power is inversely proportional to the absolute temperature and the activation energy for ionic conduction is equal to the heat of transport. The results explain experiments fairly good.
TL;DR: In this article, the resistivity, thermoelectric power and Hall constant of polycrystalline Th 3 As 4 samples obtained by annealing thin thorium slabs in arsenic vapour were determined.
TL;DR: In this paper, the thermoelectric power of Fe-Ni alloys relative to Pt was measured up to 1050°C in the whole range of concentration and great care was given to the phase transition of the alloys.
Abstract: The thermoelectric power of Fe–Ni alloys relative to Pt was measured up to 1050°C in the whole range of concentration. Great care was given to the phase transition of the alloys. The concentration dependence of thermoelectric power in the fcc phase at high temperatures shows a distinct anomaly around 50 at% Ni, suggesting that the alloys have the tendency to separation into two fcc phases. The so-called Invar problem is considered to be closely related to this anomaly.