Nernst–Ettingshausen Effects in GaxIn1–xAs alloys

1973 ◽  
Vol 51 (22) ◽  
pp. 2369-2375 ◽  
Author(s):  
Denis J. E. Demars ◽  
John C. Woolley
Keyword(s):  
Experimental Data ◽  
Magnetic Fields ◽  
Effective Mass ◽  
Room Temperature ◽  
Optical Scattering ◽  
Temperature Measurements ◽  
Scattering Coefficient ◽  
Alloy Sample ◽  
Alloy Scattering ◽  
Good Agreement

Room temperature measurements of longitudinal and transverse Nernst–Ettingshausen coefficients [Formula: see text] have been made on samples of GaxIn1–xAs alloys for a range of magnetic fields (B) up to 3.2 Wb/m2. Previous theoretical expressions for the values of these coefficients have been extended to the case of electrons in a single Kane band, and hence expressions for [Formula: see text] and [Formula: see text] obtained in terms of B, the bottom of the band effective mass m0*, and the scattering coefficient s. Fitting of these expressions to the experimental data thus has given values of m0* and s for each alloy sample. The values of m0* are found to be in good agreement with those obtained previously from plasma reflectance work, while the values of s indicate that over most of the alloy range polar optical scattering is predominant, but that in the range 0.4 < x < 0.7, alloy scattering may also have some contribution.

Electron effective mass values in GaAsxSb1−x alloys

1981 ◽  
Vol 59 (7) ◽  
pp. 939-944 ◽  
Author(s):  
Paul Devlin ◽  
Hassan M. Heravi ◽  
John C. Woolley
Keyword(s):  
Experimental Data ◽  
Effective Mass ◽  
Conduction Band ◽  
Faraday Rotation ◽  
Room Temperature ◽  
Electron Effective Mass ◽  
Kane Model ◽  
Experimental Variation ◽  
Infra Red ◽  
Best Fit

Measurements of Faraday rotation and of infra-red plasma reflectance have been made at room temperature on n-type polycrystalline samples of GaASxSb1−x alloys. Hence effective mass values m00* for the bottom of the (000) conduction band have been determined. The experimental variation of m00* with x is compared with the predictions of various models, viz., (a) a simple Kane model, (b) the model proposed by Berolo et al., and (c) the model proposed by Hermann and Weisbuch. It is found that the model of Berolo et al. gives the best fit to the experimental data.

LARGE ROOM TEMPERATURE MAGNETORESISTANCE IN (La0.7Sm0.3)0.7Sr0.3MnO3/Agx COMPOSITES

2005 ◽  
Vol 19 (30) ◽  
pp. 4467-4473 ◽  
Author(s):  
XIAO-BO YUAN ◽  
YI-HUA LIU ◽  
CHENG-JIAN WANG ◽  
LIANG-MO MEI
Keyword(s):  
Experimental Data ◽  
Grain Boundaries ◽  
Room Temperature ◽  
Composite System ◽  
Molar Ratio ◽  
Ag Addition ◽  
Brillouin Function ◽  
Spin Clusters ◽  
Good Agreement

The effects of Ag addition in the composite ( La 0.7 Sm 0.3)0.7 Sr 0.3 MnO 3/ Ag x (abbreviated as LSSMO/Ag x) has been studied. The results showed that Ag addition induces the decrease in resistivity (ρ) due to the improvement of grain boundaries resulted from the segregation of Ag on the grain surfaces. In addition, 27% molar ratio of Ag addition induces a large room temperature magnetoresistance (MR) ratio of 35%. The good agreement of experimental data with Brillouin function indicates that the MR behavior in this composite system accounts for the spin-dependent hopping of the electrons between the spin clusters.

Ligand Redistribution Equilibria in Aqueous Fluoroberyllate Solutions

1998 ◽  
Vol 53 (11) ◽  
pp. 1294-1300 ◽  
Author(s):  
Michael Schmidt ◽  
Hubert Schmidbaur
Keyword(s):  
Experimental Data ◽  
Ligand Exchange ◽  
Room Temperature ◽  
Chemical Shifts ◽  
Equilibrium Constants ◽  
Individual Species ◽  
Ph Values ◽  
Exchange Processes ◽  
The Individual ◽  
Good Agreement

The composition of aqueous fluoroberyllate solutions has been studied by 9Be and 19F NMR spectroscopy for various ratios of the beryllium and fluorine concentrations, and at different pH values. The equilibrium constants have been determined for the ligand exchange processes, which involve the species [Be(OH2)4]2+, [BeF(OH2)3]+, [BeF2(OH2)2], [BeF3(OH2)]- , and [BeF4]2-. These equilibria are shifted towards [BeF4]2- at high pH. No polynuclear fluoroberyllates have been detected. The fluoride exchange between the individual species is slow on the NMR time scale at room temperature, and separate sharp signals with the expected multiplicity are therefore recorded. Calculated 9Be chemical shifts are in good agreement with experimental data.

Conduction band of InAs

1968 ◽  
Vol 46 (15) ◽  
pp. 1669-1675 ◽  
Author(s):  
Clarence C. Y. Kwan ◽  
John C. Woolley
Keyword(s):  
Magnetic Fields ◽  
Hall Effect ◽  
Valence Band ◽  
Conduction Band ◽  
Infrared Absorption ◽  
Room Temperature ◽  
Impurity Content ◽  
Temperature Measurements ◽  
Energy Separation ◽  
Transverse Magnetoresistance

Measurements of transverse magnetoresistance and Hall effect have been made at 4.2 °K on various In2Se3-doped and In2Te3-doped InAs polycrystalline specimens with magnetic fields up to 3.2 Wb/m2. An analysis of the results gives values of electron concentrations n0 and n1 and mobilities μ0 and μ1 for both the (000) and [Formula: see text] conduction-band minima. From the values of n0 and n1, the energy separation of the (000) and [Formula: see text] minima E01 of pure InAs has been determined to be 0.70 + 0.02 eV and is found to decrease with increasing impurity content, the rate of reduction being 0.13 ± 0.02 eV/at.% selenium and 0.17 ± 0.03 eV/at.% tellurium. Room-temperature measurements of electroreflectance and infrared absorption have also been made, and these indicate that the variation in E01 is due to the movement of the (000) conduction-band minimum relative to the valence band.

Electron effective-mass values in GaxIn1−xSb alloys

1969 ◽  
Vol 47 (6) ◽  
pp. 631-636 ◽  
Author(s):  
Marcel J. Aubin ◽  
Mathew B. Thomas ◽  
Eric H. van Tongerloo ◽  
John C. Woolley
Keyword(s):  
Effective Mass ◽  
High Frequency ◽  
Room Temperature ◽  
Composition Range ◽  
Bridgman Technique ◽  
Scattering Parameter ◽  
Electron Effective Mass ◽  
High Frequency Dielectric Constant ◽  
The Matrix ◽  
Good Agreement

Room-temperature measurements of Faraday rotation, magneto–thermoelectric power, and infrared reflectance have been made on homogeneous coarsely polycrystalline n-type samples of GaxIn1−xSb alloys produced by the horizontal Bridgman technique. Using these data and a Kane equation for the (000) conduction band, values of the bottom of the band effective mass m00* have been determined over the composition range 0 < x < 0.85, i.e. the range in which the subsidiary [Formula: see text] minima make no contribution. The results from the three different techniques show very good agreement. From the data, values are obtained also for the square of the matrix element P2, the high-frequency dielectric constant ε∞, and the scattering parameter s for the various alloy specimens.

Springback Behavior of an Invar Sheet and Its Perforated Form

2006 ◽  
Vol 505-507 ◽  
pp. 781-786
Author(s):  
Yi Che Lee ◽  
Fuh Kuo Chen
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Tensile Tests ◽  
Test Results ◽  
Bending Tests ◽  
Predicted Values ◽  
Springback Behavior ◽  
Good Agreement

The springback behavior of an invar sheet and its perforated form were examined in the present study. The mechanical properties for invar sheet and perforated invar-sheet at elevated temperatures were first obtained from tensile tests. The test results suggest that both invar sheet and perforated invar-sheet have favorable formability at temperature higher than 200oC. An analytical model was also established to predict the springback of the invar sheet and its perforated form under bending conditions at various elevated temperatures. In order to verify the predicted results, the V-bending tests were conducted for the invar sheet at various temperatures ranging from room temperature to 300. The experimental data indicate that the springback decreases with the rise in temperature for both invar sheet and perforated invar-sheet. The good agreement between the experimental data and the predicted values confirms the validity of the proposed theoretical model as well.

Phonon Thermal Conductivity of Superlattice Nanowires for Thermoelectric Applications

2003 ◽  
Vol 793 ◽  
Author(s):  
C. Dames ◽  
M. S. Dresselhaus ◽  
G. Chen
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Size Effects ◽  
Three Dimensional ◽  
Small Diameter ◽  
Particle Model ◽  
Phonon Thermal Conductivity ◽  
Alloy Scattering ◽  
Classical Size ◽  
Good Agreement

ABSTRACTAn incoherent particle model has been developed to predict the phonon thermal conductivity of nanowires and superlattice nanowires. It is argued that the surface roughness of most real nanowires prevents the formation of idealized confined dispersion relations for typical temperatures and diameters. Instead, the three-dimensional bulk dispersion is used, thus addressing only classical size effects. Four adjustable parameters capture the effects of diameter, superlattice, Umklapp, impurity, and alloy scattering. Predictions are compared with experimental data for nanowires and superlattice nanowires down to 22 nm diameter and 20 K, and are in good agreement above ∼40 nm diameter. The analysis suggests that ideal low thermal conductivity nanowires for thermoelectric applications would have small-diameter, alternating alloy segments that are acoustically dissimilar but electrically similar.

Plasma Edge Reflectance Measurements in GaxIn(1−x)As and InAsxSb(1−x) Alloys

1971 ◽  
Vol 49 (15) ◽  
pp. 2052-2060 ◽  
Author(s):  
Mathew B. Thomas ◽  
John C. Woolley
Keyword(s):  
Experimental Data ◽  
Relaxation Time ◽  
Effective Mass ◽  
Conduction Band ◽  
Room Temperature ◽  
Plasma Edge ◽  
Electron Effective Mass ◽  
Reflectance Measurements ◽  
Type Conduction

Room temperature measurements of plasma reflectance have been made on polycrystalline homogeneous n type samples of GaxIn(1−x) As and InAsxSb(1−x) alloys. An analysis for the case of general degeneracy in a Kane-type conduction band has been developed, to allow the determination of electron effective mass (m0*/m) at the bottom of the conduction band. Hence values of m0*/m vs. x have been determined for both alloy systems. From the experimental data, values of relaxation time and optical mobility have also been calculated.

scholarly journals Experimentelle und semi-empirische Protonen-Hyperfein- kopplungen von 1.3-Benzodioxol-Radikal-Kationen und ihre Korrelation mit Reaktivitäten in elektrophilen Substitutionen

1982 ◽  
Vol 37 (7) ◽  
pp. 680-687 ◽  
Author(s):  
Jörg Fleischhauer ◽  
Sun Ma ◽  
Wolfgang Schleker ◽  
Klaus Gersonde ◽  
Hans Twilfer
Keyword(s):  
Experimental Data ◽  
Perturbation Theory ◽  
Hyperfine Splitting ◽  
Electrophilic Substitution ◽  
Room Temperature ◽  
Hydrogen Atoms ◽  
Substitution Reactions ◽  
X Band ◽  
Band Spectra ◽  
Good Agreement

Abstract The solution ESR X-band spectra of 1.3-benzodioxole (methylenedioxybenzene) (1), benzo- [1.2-d:4.5-d']bis[1.3]dioxole (2), benzo[1.2-d:3.4-d']bis[1.3]dioxole (3) and benzotris[1.3]dioxole (4) have been measured at room temperature. Hyperfine splitting constants of the aromatic ring protons of the compounds 1 - 3 have been determined. They have been correlated with the HOMO orbital densities of the adjacent carbon atoms and exhibit sufficient correspondence with the reactivities of these compounds in electrophilic substitution reactions. The splitting constants of all protons of the compounds 1 - 4 have been calculated by the INDO and HMO methods and have been compared with the experimental hyperfine values. By perturbation theory applied to the interactions between the π-MO'S of benzene and the dioxole fragment one can explain and understand the magnitudes of the experimental hyperfine splitting constants of the hydrogen atoms of these compounds. In particular, the hyperfine values of the methylene protons calculated by the HMO method are in good agreement with the experimental data.

Prediction of Yield in Ductile Materials Operating at Creep Temperatures

1977 ◽  
Vol 99 (3) ◽  
pp. 425-428
Author(s):  
G. M. Kurajian ◽  
T. Y. Na
Keyword(s):  
Experimental Data ◽  
Elevated Temperature ◽  
Yield Strength ◽  
Yield Point ◽  
Room Temperature ◽  
Ductile Metals ◽  
Ductile Materials ◽  
Machine Element ◽  
Creep Temperature ◽  
Good Agreement

Utilizing a thermodynamic approach, this paper provides the designer with formulations and data so that he can obtain or verify, and then employ, the yield strength (or yield point) value he may desire in the design of a particular ductile machine element operating in the creep temperature range. A previous paper by the authors [1] dealt with the prediction of failure of such elements in the range between room temperature and the lower creep temperature. Thus, the present paper in conjunction with [1], and the references in both, is to provide a thermodynamic explanation for failure of such elements operating in elevated temperature environments ranging from room through creep temperatures. Specific applications are taken for three selected categories of steel with good agreement between the theory and experimental data. However, with necessary data, the procedures in this paper, as it was in [1], is expected to be applicable to other ductile metals as well.

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