Showing papers on "Seebeck coefficient published in 1973"
TL;DR: In this paper, the electrical resistivity, the thermoelectric power, and the Hall coefficient for Fe(n) 2 doped with Mn or Co have been measured over the temperature range 300-1400 K. The added Mn acts as an acceptor.
Abstract: The electrical resistivity, the thermoelectric power, and the Hall coefficient for Fe${\mathrm{Si}}_{2}$ doped with Mn or Co have been measured over the temperature range 300-1400 K. The energy gaps deduced from the slopes of curves of the resistivity versus reciprocal absolute temperature decrease with increasing Mn concentration. The resistivities and thermoelectric powers show a semiconductor-to-metal transition with hysteresis, and the transition temperature decreases with increasing Mn concentration. Specimens both doped with Mn and undoped are found to be $p$-type semiconductors in the temperature range below the transition temperature. The added Mn acts as an acceptor. The analysis of resistivity in the semiconducting state was based on a model predicting that the narrow band in the metallic state is split by the crystalline-structure distortion. The density of states for the undoped specimen is found to be 7.46\ifmmode\times\else\texttimes\fi{}${10}^{22}$ ${\mathrm{cm}}^{\ensuremath{-}3}$. Assuming that the value of the density of states is invariable in all specimens, the analyzed results are in reasonable agreement with the resistivities observed in the intrinsic region.
212 citations
TL;DR: The absolute Seebeck coefficient of platinum was determined from 80 to 340 K by direct comparsion to lead as discussed by the authors, which was within 1% of the Sommerfeld value of 2.443×10−8 (V/K)2 from 1.0 to 5.0 ΘD.
Abstract: The absolute Seebeck coefficient of platinum was determined from 80 to 340 K by direct comparsion to lead. Results of this comparison disagree with previous results which have been used for the calculation of absolute values for other materials. The thermal conductivity λ and electrical resistivity ρ of the lead standard were also determined. The electrical resistivity could be described with a modified Gruneisen‐Bloch equation which allows for the effect of thermal expansion on the Debye temperature ΘD. The ratio λρ/T was within 1% of the Sommerfeld value of 2.443×10−8 (V/K)2 from 1.0 to 5.0 ΘD.
104 citations
TL;DR: In this paper, a galvanic cell is used to detect the electrochemical potential of Ag +, since the interdiffusion of Cu + into AgI is nearly forbidden except near Cu 2 Se.
Abstract: The phase diagram is studied by X-ray and thermal analyses. The high temperature phase (α) is the solid solution of b.c.c. or f.c.c. in which Ag + , Cu + and electron are mobile. The galvanic cell Ag|AgI|specimen|Pt is available to controle the excess or deficit Ag density and to detect the electrochemical potential of Ag + , since the interdiffusion of Cu + into AgI is nearly forbidden except near Cu 2 Se. With the help of the cell and utilizing the weight-difference between Ag and Cu, the polarization and the interdiffusion are measured and interpreted with the diffusion theory. The electronic and ionic conductivities are measured with varying temperature and x . Further the various properties of α(Ag, Cu) 2 Se such as the conductivity, Hall coefficient, thermoelectric power, thermal conductivity etc. are measured and compared with the theory, indicating that the energy gap decreases with increasing x .
99 citations
TL;DR: A variety of compositions of glass in the As-Te series have been prepared and structurally analyzed using x-ray powder diffraction, density determinations, and differential-scanning-calorimetry experiments as discussed by the authors.
Abstract: A variety of compositions of glass in the As-Te-I, As-Te-Ge, and As-Te chalcogenide series have been prepared and structurally analyzed The analytical techniques included x-ray powder diffraction, density determinations, and differential-scanning-calorimetry experiments The temperature dependence of the Hall mobility, Seebeck coefficient, and dc conductivity was determined for six representative alloy compositions The Hall mobility was found to be $n$-type, low, and activated with nearly equal activation energies in each case The conductivity mobility was deduced from the $p$-type Seebeck coefficients and the conductivity measurements to have an activated character with a characteristic energy of 019 \ifmmode\pm\else\textpm\fi{} 002 eV for all the measured compositions These results appear to be inconsistent with the familar Cohen-Fritzsche-Ovshinsky (CFO) picture for transport in amorphous semiconductors, and a new model for conduction in these glasses is proposed This model involves the hopping of holelike small polarons between sites associated with a common As-Te structural entity which is postulated to be present in all the alloys measured here The sign, magnitude, and temperature dependence of the dc conductivity, Seebeck coefficient, and Hall mobility are all consistent with this model
78 citations
TL;DR: In this article, thermopower, resistivity, and thermal conductivity for the rare earth intermetallic compounds CePd3 and CeIn3 indicate an anomalously large Peltier effect cooling figure of merit at low temperatures associated with a large power source.
Abstract: Measurements of thermopower, resistivity, and thermal conductivity for the rare‐earth intermetallic compounds CePd3 and CeIn3 indicate an anomalously large Peltier effect cooling figure of merit at low temperatures associated with a large thermopower. Resistivity and susceptibility measurements indicate that these compounds possess localized Ce 4f electrons which give rise to the Kondo effect and thermopower enhancement. These results suggest that a survey of Ce intermetallic compounds could lead to new materials for low‐temperature thermoelectric cooling applications.
64 citations
TL;DR: In this article, measurements of thermoelectric power, resistivity, and temperature coefficient of resistance have been made on annealed silver films, and the values obtained for the energy dependence of the mean free path of conduction electrons, [(∂ lnλ/∂ LnW)]W=WF, and for the Fermi surface area, [1.29 and −2.45]
Abstract: Measurements of thermoelectric power, resistivity, and the temperature coefficient of resistance have been made on annealed silver films. The values obtained for the energy dependence of the mean free path of conduction electrons, [(∂ lnλ/∂ lnW)]W=WF, and the Fermi surface area, [(∂ lnA/∂ lnW)]W=WF, were 1.29 and −2.45, respectively.
50 citations
TL;DR: In this article, the thermal conductivity, electrical resistivity, and thermoelectric power of polycrystalline specimens of pure Co have been determined in the temperature range of 90 to 1250
Abstract: The thermal conductivity, electrical resistivity, and thermoelectric power of well-characterized, polycrystalline specimens of pure Co have been determined in the temperature range of 90 to 1250 K. Additionally, the measurements of the electrical resistivity have been extended to 1750 K, and the coefficient of thermal expansion measured between 300 and 770 K. The new results are compared with those previously published, and, for the low temperature h.c.p. phase, compared with predictions based on published band structure calculations. Qualitatively, the observed results agree with the predictions, particularly as far as the very unusual temperature variation of the Lorenz function is concerned; quantitative comparisons, however, are impossible, due to the lack of precision in the calculated band structures. The theoretical analysis of the results for the high temperature f.c.c. phase will be given together with that of Ni in Part II.
43 citations
TL;DR: In this article, an analysis of transport properties has been carried out using a general energy dependence of the relaxation time, τ =aEb, and it has been shown by the analysis that if b=− 1 2 there should be a size effect in the electrical conductivity, but the Seebeck coefficient is independent of size.
38 citations
TL;DR: In this paper, the authors studied tellurium films formed at various substrate temperatures in order to find their resistance R, activation energy ΔE, Hall coefficient RH, mobility μ, carrier concentration n, thermoelectric power α, TCR etc.
34 citations
TL;DR: In this paper, a correlation between intrinsic film stress and output voltage suggests that the stress gives rise to a nonscalar absolute thermoelectric power (Seebeck coefficients) even though the transport properties of these bulk materials are isotropic.
Abstract: Transverse thermoelectric voltages have been observed to occur when thin Mo and W films are excited by pulsed laser light at normal incidence to the film. Wavelengths in the range 0.46–1.06 μm and pulse widths of ∼ 3–300 nsec were used. A maximum thermoelectric voltage of ∼50 mV occurring across a load resistance of 50 Ω for an ∼ 1‐kW incident laser pulse has been observed. A correlation between intrinsic film stress and output voltage suggests that the stress gives rise to a nonscalar absolute thermoelectric power (Seebeck coefficients) even though the transport properties of these bulk materials are isotropic.
31 citations
TL;DR: In this article, the exact and approximate forms of the function F(K) for various theories of the scattering mechanism at the film surfaces are reported, and plots of the derived expressions using some of these forms are given.
TL;DR: In this paper, the electrical resistivity and thermopower of liquid Ca, Sr and Ba based on the t matrix formulation of the nearly free electron theory is calculated. But the results are in reasonable agreement with the experimental data and they argue that the large resistivity of Ba, 306 mu Omega cm, results primarily from a large d contribution to the electron-ion scattering cross section.
Abstract: The authors present calculations of the electrical resistivity and thermopower of liquid Ca, Sr and Ba based on the t matrix formulation of the nearly free electron theory. The results are in reasonable agreement with the experimental data and we argue that the large resistivity of Ba, 306 mu Omega cm, results primarily from a large d contribution to the electron-ion scattering cross section.
TL;DR: In this article, the temperature dependence of the resistivity and the thermoelectric power of rare earths have been measured and the tetragonal lattice of La2CuO4 shrinks in the a axis and expands in the c axis.
Abstract: The temperature dependence of the resistivity and the thermoelectric power of Ln2CuO4 (Ln=rare earths) have been measured. The compounds of Gd, Sm, Nd, and Pr are semiconductive, while La2CuO4 shows metallic conductivity. The tetragonal lattice of La2CuO4 shrinks in the a axis and expands in the c axis compared to Pr2CuO4, in spite of the steady expansion of these lattice parameters for the compounds between Gd and Pr. The thermoelectric power of Ln2CuO4, but not La2CuO4, is negative, suggesting an electron-conducting or n-type semiconductor. The resistivity of the Ln2CuO4 at room temperature increases essentially with an increase in the atomic number of Ln. The plots of the thermoelectric power vs. the reciprocal temperature showed a steeper slope for the compounds of the heavier rare earths. The semiconductor-metal transition observed between La2CuO4 and Pr2CuO4 was explained in relation to the structural change (the shrinkage of the a axis and the expansion of the c axis) as being due to the change in ...
TL;DR: The thermoelectric powers of cerium, lanthanum, nickel and cobalt have been measured at temperatures just above and just below the melting point as discussed by the authors, which seem to conform to a general pattern of behaviour.
Abstract: The thermoelectric powers of cerium, lanthanum, nickel and cobalt have been measured at temperatures just above and just below the melting point. The results, which seem to conform to a general pattern of behaviour, are compared with the other electronic transport parameters.
TL;DR: In this paper, a new technique was developed for high resolution absolute thermoelectric power (TEP) and differential TEP measurements using dc nanovolt amplifiers, where the outputs of these amplifiers are attached to the channels of an X-Y recorder, thus yielding direct slopeproportional data.
Abstract: A new technique, principally applicable to metals and alloys, has been developed for high resolution absolute thermoelectric power (TEP) and differential thermoelectric power measurements. It utilizes two continuously monitoring dc nanovolt amplifiers, one for the sample couple thermoelectric voltage and the other for a thermocouple voltage proportional to temperature differences developed across the samples. The outputs of these amplifiers are attached to the channels of an X‐Y recorder, thus yielding direct slope‐proportional data. By using heat from a low‐mass, electrostatically guarded heater to develop transient temperature gradients across samples, it is possible to dynamically determine the absolute TEP of a sample versus lead (Pb) or the differential TEP of two nearly similar samples, one of whose composition or history of treatment has been slightly altered. Reducing thermal time constants with an independent heat leak permits the completion of a TEP measurement in a few seconds, thus yielding hi...
TL;DR: In this paper, the three-dimensional network of As 2 Se 3 is assumed to be modified by the Tl atoms; this leads mainly to a decrease in the activation energy.
Abstract: Dc conductivity and thermopower measurements as a function of temperature have been performed on solid As 2 Se 3 Tl x glasses with x ranging from 0 to 1.99. Investigations have been extended to low temperatures. By substitution of Tl the conductivity can be increased by more than 5 orders of magnitude without changing the type of transport mechanism. Band-like conduction is observed with holes being the dominant charge carriers. The three-dimensional network of As 2 Se 3 is assumed to be modified by the Tl atoms; this leads mainly to a decrease in the activation energy.
TL;DR: The thermoelectric powers of pure metals Mg, Ca, Sr, and Ba have been measured across their melting points as mentioned in this paper, and the measured liquid thermopowers indicate a progressively increasing energy dependence of the pseudopotentials with increasing atomic number.
Abstract: The thermoelectric powers, S, of the pure metals Mg, Ca, Sr, and Ba have been measured across their melting points. The values obtained for the liquids at the melting point are: Mg, 1.6 mu V degrees C-1; Ca, 9.9 mu V degrees C-1; Sr, -0.4 mu V degrees C-1; Ba, -0.2 mu V degrees C-1. S shows little change with melting for Ca, Sr, and Ba; for Mg, S changes sign upon melting. The measured liquid thermopowers, in light of recent resistivity data for these liquids, indicate a progressively increasing energy dependence of the pseudopotentials with increasing atomic number (Mg to Ba). The temperature dependence of the thermopower, dS/dT, for these liquids is discussed in terms of a simple theory.
TL;DR: In this paper, the resistivity and thermoelectric power of liquid Cs under pressure up to 40 kbar have been derived in a t matrix formulation of Ziman's theory.
Abstract: Calculations of the resistivity and thermoelectric power of liquid Cs under pressure up to 40 kbar have been made, in a t matrix formulation of Ziman's theory. The calculations are dominated by the behaviour of the d phaseshifts and agree well with experiment.
TL;DR: In this article, the thermoelectric power of two crystals of AgCl doped with Mn2+ ions has been measured over a range of temperatures from 97 to 414 degrees C using Ag electrodes.
Abstract: The thermoelectric power of two crystals of AgCl doped with Mn2+ ions has been measured over a range of temperatures from 97 to 414 degrees C using Ag electrodes. These data, and also earlier data for pure AgCl and for AgCl doped with Cd2+ ions have been shown to be fully consistent with the assumption that the heats of transport, and also another related parameter, are independent of temperature. The value of the heat transport for Ag+ ions migrating on the cation sublattice by a vacancy mechanism (QM) is 0.311 eV, while the values for the collinear (Qic) and noncollinear (Qinc) mechanisms are -0.180 eV and -1.20 eV respectively. These numerical values are consistent with elementary theories of the heat of transport.
TL;DR: In this article, the electrical resistivity and thermopower of the noble metals and nickel are calculated based on a model similar to the simple nearly free electron model used for the liquid transition metals.
Abstract: Calculations of the electrical resistivity and thermopower of the noble metals and nickel are presented. They are based on a model similar to the simple nearly free electron model used for the liquid transition metals. The scattering of the Bloch functions is described by the t matrix of a single muffin tin potential. The positive sign of the thermopower of the noble metals can be explained in terms of the magnitude of the backward scattering cross section using an argument similar to that applied in the liquid case. The peculiar shape of the Fermi surface need not be invoked in order to explain this sign.
TL;DR: In this paper, the thermoelectric power and electrical conductivity of cesium were measured at subcritical and supercritical temperatures to 1800°C and at different pressures.
TL;DR: In this paper, the thermoelectric power of very well oriented, nearly single-crystal graphite irradiated at 333 K by 3 MeV electrons was measured along the basal plane direction above 5 K.
TL;DR: In this article, resistivity in the range of 100 Hz to 100 MHz and thermoelectric power were measured for CoFe 2- x Ti x O 4 and Co 1- x Fe 2+X O 4 single crystals (x = 0.06, 0.10 and 0.14) in the temperature range between 78 and 300 K.
Abstract: The a. c. resistivity in the range of 100 Hz to 100 MHz and thermoelectric power were measured for CoFe 2- x Ti x O 4 and Co 1- x Fe 2+ x O 4 single crystals ( x =0.06, 0.10. and 0.14) in the temperature range between 78 and 300 K. Electrical properties are quite similar for both systems. The concentration of electron carriers increases exponentially with increasing temperature. Its activation energy decreases with increasing ferrous ion contents ( x ). The mobility takes the value of 2×10 -2 cm 2 /V.sec at 300 K and decreases with decreasing temperature. Its activation energy is about 0.05 eV and dose not depend on x . The electrical conduction for both systems is satisfactorily explained in terms of the small-polaron hopping model.
TL;DR: In this article, a modified version of the Nordheim-Gorter rule has been used to obtain the contribution from scattering by the Ce atoms, and the results up to 70 K can be understood in terms of the model of nonmagnetic 4f states.
Abstract: Measurements of thermoelectric power have been made on someThCe alloys in the temperature range 2–300 K. A modified version of the Nordheim-Gorter rule has been used to obtain the contribution from scattering by the Ce atoms. The results up to 70 K can be understood in terms of the model of nonmagnetic 4f states in agreement with other recent work on this alloy system.
TL;DR: In this paper, the phonon spectrum is calculated by the Born-von Karman atomic-force-constant model and the matrix elements of the electron-phonon interaction are given by the single. site approximation.
Abstract: The thermoelectric power of copper at high temperature is calculated by a realistic model. The Fermi vector, Fermi velocity and wave functions are determined by APW. The phonon spectrum is calculated by the Born-von Karman atomic-force-constant model. The matrix elements of the electron-phonon interaction are given by the single. site approximation. It is found that the calculated value of the thermoelectric power has a positive sign and its magnitude is roughly equal to the observed one.
TL;DR: In this paper, the electronic component of the thermoelectric power of metals is discussed in the case when a unique relaxation time cannot be defined, and it is argued that the relaxation time to be used in the standard expression should be a relaxation time appropriate to isothermal electrical conduction.
TL;DR: In this paper, electrical conductivity and Seebeck coefficient of semiconducting EuB 6 and YbB 6 were compared in terms of a band model in which the conduction band is the 5d or 6s band of the rare-earth sublattice.
TL;DR: In this article, the electrical resistivity and thermoelectric power of Fe-0.1 wt.% N alloy have been examined during aging at 25°C and it is suggested that strong co-operative scattering does not occur in this alloy because of the small concentration ratio of solute to solvent in the preprecipitate zone.
TL;DR: In this article, some doping effects on the semiconducting properties of the Gd2CuO4 compound were investigated, and the results indicated that the dopant of BaO was less effective on the resistivity-lowering than was the CaO.
Abstract: Some doping effects on the semiconducting properties of the Gd2CuO4 compound were investigated. The ZrO2 or ThO2 (0.5 mol%) lowered the resistivity of the Gd2CuO4 at room temperature by a factor of 104. The thermoelectric powers of the same samples were negative. These were explained as being due to the Cu+ ions formed by the dopants. The CaO dopant lowered the resistivity by a factor of ten and converted the sign of the thermoelectric power from negative to positive. The resistivity of the BaO-doped samples increased with an increase in the dopant concentration up to 0.5 mol%, and decreased with an increase in the dopant concentration in the concentration region lower than that. This suggested that the dopant of BaO was less effective on the resistivity-lowering than was the CaO. The samples doped with the ZrO2 and CaO simultaneously gave a trend similar to those doped with the BaO in the concentration dependence of the resistivity. Silver oxide and indium oxide were also employed as dopants, but no dopi...
TL;DR: In this article, an alternative interpretation of the thermoelectric data of Tang, Craig, and Kitchens is presented, based on the work of the authors of this paper.
Abstract: An alternative interpretation is offered of the thermoelectric data of Tang, Craig, and Kitchens.