Showing papers on "Atmospheric temperature range published in 1980"
TL;DR: Oxygen interaction with the Pt(111) surface has been studied by low energy electron loss (EELS), ultraviolet photoemission (UPS) and thermal desorption (TDS) spectroscopies over the temperature range 100 to 1400 K as mentioned in this paper.
747 citations
TL;DR: Oxygen adsorption and desorption were studied on the Pt(111 and Pt(S)-12(111) × (111) surfaces over the 100 to 1300 K temperature range in this paper.
372 citations
TL;DR: The change in viscosity of a Pd 82 Si 18 glass during isothermal annealing has been measured in the temperature range of 424-537 K for times up to 325 h as mentioned in this paper.
345 citations
TL;DR: In this article, the activation energy for steady-state creep (Qss) was found to be equal to about 87 kj mole−1 which corresponds quite closely to the activation energies for dislocation pipe diffusion as measured by Volin, Lie and Balluffi using a void shrinkage analysis.
199 citations
TL;DR: In this paper, the ferroelectric properties of (Na0,5Bi 0,5,5TiO3) single crystals are studied and it is found that some physical characteristics possess a large temperature hysteresis in the temperature range 200 − 300°C.
Abstract: The ferroelectric properties of (Na0,5Bi0,5TiO3) single crystals are studied It is found that some physical characteristics possess a large temperature hysteresis in the temperature range 200 – 300°C The nature of that hysteresis is discussed
185 citations
TL;DR: In this article, a detailed LEED study is reported of the surface phases stabilised by hydrogen chemisorption on W {001, over the temperature range 170 to 400 K, correlated with absolute determinations of surface coverages and sticking probabilities.
158 citations
TL;DR: In this article, it was found that polycrystalline films are formed above 600°C and are more stable than the amorphous films deposited at lower temperatures, depending primarily on the deposition temperature.
Abstract: Silicon films deposited by low pressure chemical‐vapor deposition over the temperature range from 525° to 725°C were investigated. It was found that polycrystalline films are formed above 600°C and are more stable than the amorphous films deposited at lower temperatures. Their crystal structure is a strong function of the deposition temperature and a weaker function of the deposition rate. Either the {110} or the {100} texture may dominate the structure, depending primarily on the deposition temperature. The electrical resistance obtained on doping the LPCVD films that are polycrystalline as deposited is maximum for films deposited at the lower temperatures (near 600°C), although this dependence on deposition temperature decreases after annealing at higher temperatures. Dopant atoms reversibly segregate to the grain boundaries during lower temperature heat‐treatments subsequent to doping and are dispersed at higher temperatures, with corresponding changes in resistivity. The oxidation rate is only a weak function of the deposition temperature, although the initially amorphous films may oxidize somewhat more rapidly. The index of refraction of amorphous films is significantly higher than that of polycrystalline films.
155 citations
TL;DR: In this article, measurements were made of the dielectric constant along the ferroelectric axis e a, the spontaneous polarization P s and the heat capacity c p of Rb 2 ZnCl 4 crystals in the temperature range from -150^° C to 150°C.
Abstract: Measurements were made of the dielectric constant along the ferroelectric axis e a , the spontaneous polarization P s and the heat capacity c p of Rb 2 ZnCl 4 crystals in the temperature range from -150^° C to 150°C. The normal-incommensurate transition point determined as the peak position of c p lies at 30.1°C, which is about 6°C lower than the temperature for the maximum of e a . It was found that e a and P s show a characteristic thermal hysteresis over a wide temperature range including the incommensurate-commensurate trarasition point (-80^° C ). The thermal hysteresis occurs even when heating and cooling runs are cycled within the incommensurate phase. The observed thermal hysteresis is understood if we assume that defects such as impurities act as obtacles to diffusion of discommensurations and prevent the crystal from reaching thermal equilibrium.
146 citations
TL;DR: In this article, the influence of oxygen on the resistivity of dislocation-free silicon wafers was studied after annealing at various temperatures under a nitrogen ambient, and significant resistivity shifts were observed in the temperature range 600 −900°C and related to oxygen precipitation.
Abstract: The influence of oxygen on the resistivity of dislocation‐free silicon wafers was studied after annealing at various temperatures under a nitrogen ambient. Significant resistivity shifts were observed in the temperature range 600–900 °C and related to oxygen precipitation. This phenomenon is independent of the well‐known donor generation observed around 450 °C and is more difficult to cure.
132 citations
TL;DR: In this article, the thermal behavior of beta-lactoglobulin in aqueous solutions was followed by differential scanning calorimetry in the temperature range from 40 to 100 degrees C. From the results the following information was obtained.
131 citations
TL;DR: In this paper, the resistivity and magnetoresistance of a single crystal were measured in the temperature range from 1.3 to 300 K under the magnetic field up to 85 kOe.
TL;DR: The temperature dependence of elastic, dielectric, and piezoelectric constants for the film of 55/45% VDF-TrFE copolymer suggests that the Curie temperature exists at about 70°C as discussed by the authors.
Abstract: The measurement of the temperature dependence of elastic, dielectric, and piezoelectric constants for the film of 55/45% VDF‐TrFE copolymer suggests that the Curie temperature exists at about 70 °C. The lattice spacing sharply changes at a temperature range from 55 to 75 °C. The remanent polarization is also determined from the D versus E hysteresis loop below 75 °C. It is found that the spontaneous strain in crystal lattice is linearly related to the square of remanent polarization. The transition is ascribed to electrostriction due to dipolar orientation.
TL;DR: In this paper, the growth rate and crystalline structure of tin oxide layers doped with antimony were studied as functions of the deposition parameters, independent of substrate type, dopant concentration, and time deposition.
TL;DR: In this article, the decomposition of ∆-ferrite to austenite has been studied in a 26%Cr-5%Ni stainless steel, and it was shown by STEM microanalysis that Ni partitions to the Austenite and Cr partitions to ferrit.
Abstract: The decomposition of ∆-ferrite to austenite has been studied in a 26%Cr-5%Ni stainless steel The decomposition takes place via two mechanisms: by nucleation and growth in the high temperature range (650–1200°C) and by an athermal martensitic process in the low temperature range (300–650°C) The high temperature reaction exhibits growth kinetics which are intermediate between volume diffusion control and growth by a ledge mechanism The morpho-logical variants of the austenite mirror those described in the Dube morphological classification for low-alloy steels, and the steel was used as a ‘model system‘ for the study of bcc ⇄ fcc transformations In the low temperature range (400–600°C) the formation of α′, which gives rise to 475°C embrittlement, is shown to occur by a nucleation and growth process, and the subsequent dissolution of the α′ is explained by the precipitation of austenite Finally, it is shown by STEM microanalysis that Ni partitions to the austenite and Cr partitions to the ferrit
TL;DR: A detailed investigation on the thermal expansion, magnetic properties and electrical resistance of rapidly quenched amorphous (Fe,Co,Ni)-Zr alloys has been undertaken in this article.
Abstract: A detailed investigation on the thermal expansion, magnetic properties and electrical resistance of rapidly quenched amorphous (Fe,Co,Ni)-Zr alloys has been undertaken. Magnetic properties of these alloys are reported separately in this conference. The thermal expansion curves exhibit typical invar characteristics below the Curie temperature due to positive spontaneous volume magnetostriction us similar to those for Fe-Ni crystalline invar alloys. The reduced magnetization decreases strongly with increasing temperature being analogous to the case of other amorphous invar alloys. Moreover, w s at 0 K and electrical resistance at room temperature and Liq. N 2 temperature increase in the invar region. Amorphous ternary alloys of (Fe,Co, Ni) 90 Zr 10 with about 72 at% Fe have the invar characteristics in a wide temperature range and in this composition range, the volume magnetostriction and electrical resistance show maximum values of about 1.5 × 10-2and 160 μΩcm respectively.
TL;DR: In this paper, it was shown that vibrational correlations between silver ions are partly responsible for the decrease of the energy necessary for the cation hopping mechanism in β alumina 11 Al2O3.
Abstract: Single crystals of nonstoichiometric β alumina 11 Al2O3, (1+x)M2O3(x = 0.25 to 0.6) with M = Na, K, Tl, Ag have been studied by Raman spectroscopy between 2 and 1000 cm−1 in the 20–1400 K temperature range. Far infrared measurements have been performed between 10 and 250 cm−1. Ag(Ag)3 and (Tl)3 clusters of coupled cations have been evidenced in the low temperature spectra of Ag+ and Tl+ compounds. Ag–Ag and Tl–Tl ’’bond stretching’’ force constants were found equal, respectively, to 0.10 and 0.23 mdyn A−1. In the low temperature state, potential barriers separating sites available for cations have been found to increase at a small extent from x = 0 to x = 0.6 compounds. The temperature dependence of the low frequency Raman spectra is reported and shows that vibrational correlations between silver ions are partly responsible for the decrease of the energy necessary for the cation hopping mechanism.
TL;DR: In this article, the quasi-elastic spectral component of the compound CeAl3 in the temperature range 60 mK < T < 125 K was measured and it was shown that at low temperatures, below ⋍ 1 K, the spectral width is effectively constant but increases as T12 at higher temperatures.
TL;DR: In this article, the growth rate and chemical composition of thermally grown oxides on InP in dry oxygen were presented, and the oxide was found to grow very slowly below 340 °C and rapidly above this temperature.
Abstract: The growth rate and chemical composition of thermally grown oxides on InP in dry oxygen are presented. The oxide is found to grow very slowly below 340 °C and rapidly above this temperature. All the oxides grown in the temperature range 340–450 °C are composed of approximately 70%–75% In2O3 and 25%–30% P2O5. There is also some evidence for low concentrations of another bonding state of phosphorous.
TL;DR: In this article, the motion of a wire through ice by the regelation process has been measured in the temperature range −0.006 to −35°C. The motion of the wire was interpreted as an indication of a finite mobility of water in a liquid layer between the wire and the ice over this entire temperature range.
TL;DR: In this paper, single crystals of pure and carbon-substituted divalent hexaborides EuB6 and YbB6 have been prepared by the Al flux method.
Abstract: Single crystals of pure and carbon‐substituted divalent hexaborides EuB6 and YbB6 have been prepared by the Al flux method. Lattice parameters, density measurements, and microprobe analysis show that the single crystals are very close to stoichiometry. EuB6 is ferromagnetic (TC=12.5 K and ϑp=15 K) whileYbB6 is diamagnetic. Resistivity and Hall effect measurements carried out over a wide temperature range show that both pure hexaborides are semiconductors with a small intrinsic gap. The carbon‐substituted hexaborides RE B6−xCx (RE=Eu, Yb) have a metallic behavior due to the donation of electrons to the conduction band by carbon atoms. Metallic conduction, at low temperature, in the ’’pure’’ hexaborides is attributed to the formation of an impurity band containing more than 1018 electrons per cm3.
TL;DR: In this paper, molecular dynamics simulations have been performed in order to study fast-ion conduction in solid SrCl2 over a range of temperatures and densities, showing that diffusion occurs by discrete hops between regular lattice sites, the ion residence time being an order of magnitude greater than the flight time.
Abstract: Molecular dynamics simulations have been performed in order to study fast-ion conduction in solid SrCl2 over a range of temperatures and densities. The simulations are carried out on a system of 324 ions interacting through rigid-ion potentials. The anion diffusion constant increases from a very small value to a value typical of molten salts over a temperature range of about 200K, in qualitative accord with experiment, but the transition temperature is about 20% higher than the experimental one. Analysis indicates that diffusion occurs by discrete hops between regular lattice sites, the ion residence time being an order of magnitude greater than the flight time. The diffusion can be described in terms of the motion of vacancy and interstitial defects. The concentration of defects above the transition temperature is approximately 3% of vacancies per regular site.
TL;DR: In this paper, a correlation between three types of measurement technique was established and four distinct annealing stages have been identified for perfect recrystallization and maximum electrical activation in GaAs with 150 keV, 1.10 15 zinc ions and furnace annealed in the temperature range from room temperature to 900°C.
Abstract: Electrical, Rutherford backscattering and transmission electron microscopy measurements have been carried out on GaAs samples implanted with 150 keV, 1.10 15 zinc ions/cm 2 and furnace annealed in the temperature range from room temperature to 900°C. A correlation between three types of measurement technique was established and four distinct annealing stages have been identified. For perfect recrystallization and maximum electrical activation an annealing temperature of 900°C is required. The maximum peak hole concentration was in the range 1–2.10 19 holes/cm 3 .
TL;DR: In this paper, the cubic lattice parameter temperature dependence of SmB6 between 300 K and 4.2 K as well as the X-ray absorption at the LIII edge measured in the same temperature range, give direct evidence of the average samarium valence change which goes from 2.60 at 300 K to 2.53 at 4. 2 K.
Abstract: 2014 The cubic lattice parameter temperature dependence of SmB6 between 300 K and 4.2 K as well as the X-ray absorption at the LIII edge measured in the same temperature range, give direct evidence of the average samarium valence change which goes from 2.60 at 300 K to 2.53 at 4.2 K. Previous work claimed that the Sm2+ : Sm3+ ratio was temperature independent in SmB6. As for SmB6 a samarium valence change has been observed with decreasing temperature below 300 K in the Sm0.75La0.25B6 solid solution. J. Physique 41 (1980) 1141-1145 OCTOBRE 1980, Classification Physics Abstracts 78 . 70D Samarium hexaboride 5mB6 has attracted much experimental and theoretical attention in the last few years. SmB6 is a homogeneous mixed valent compound in which the Sm2+ : Sm3+ ratio at room temperature has been estimated to be about 4 : 6 from magnetic susceptibility, Mossbauer resonance measurements, LIII X-ray absorption, and X-ray photoelectron spectroscopy (XPS) [1-10]. Furthermore previous Mossbauer resonance and X-ray absorption experiments performed respectively down to l.l K and 150 K had not indicated significant variations of the SM2, : Sm 3 + ratio [3, 4, 5]. On the other hand, the lattice-parameter measurements carried out previously by us between 300 K and 4.2 K suggested a samarium valence change in SmB6 [5, 11]. In the dynamic (homogeneous) mixed valence state, each rare earth ion can be viewed as fluctuating between two configurations with the 4f shell occupation number differing by one. The charge fluctuation time ip is such that fast measurements like X-ray absorption or XPS detect both configurations separately, while slow measurements such as Mossbauer isomer shift detect only an average time, in the homogeneous mixed valent compounds. In order to determine quantitatively the samarium valence change in SmB6 as a function of temperature, X-ray absorption measurements have been carried out. The results obtained by direct observation will be compared with those deduced from lattice parameter temperature dependence. 1. Experimental. SmB6 has been prepared according to the reaction Density measurements, X-ray and chemical analysis indicate an atomic ratio B/Sm = 6. The cubic lattice parameter temperature dependence of SmB6 and SMO.7.5LaO.2.5B6 have been studied between 300 K and 4.2 K with a X-ray powder diffractometer using a monochromatic CoKa X-ray radiation [ 13]. The X-ray absorption experiments have been performed at the French synchrotron in Orsay (LURE). The X-ray beam is emitted by 1.72 GeV electrons in the ring D.C.I. The radiation was monochromatized with the help of a (220) silicon crystal. The (*) Department of Physics, Tohoku University, Sendai, Japan. Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphys:0198000410100114100
TL;DR: In this paper, the preparation, crystal structure and some physical properties of the conducting molecular (Perylene) 2 [Pt(S 4 C 4 (CN) 4 )] were reported.
TL;DR: In this paper, the emission properties of the single crystal hexaborides LaB6, CeB6 and PrB6 were measured in the temperature range between 1250 and 1700°C.
TL;DR: In this paper, the total emittance of n-type GaAs as a function of doping level and thickness in the temperature range between 300 and 1500 °K was calculated, which is related to the spectral emittance eλ, which in turn depends on the index of refraction, thickness and absorption coefficient α.
Abstract: We have calculated the total emittance et of n‐type GaAs as a function of doping level and thickness in the temperature range between 300 and 1500 °K. et is related to the spectral emittance eλ, which in turn depends on the index of refraction, thickness, and absorption coefficient α. To obtain a theoretical representation of α, a model is constructed which includes contributions by the fundamental edge, interconduction band, and free carriers (acoustic and optical phonons and ionized impurities). Since this two‐parameter model offers a good description of assorted α measurements with respect to wavelength, impurity level, and temperature, the evaluation of eλ is relatively straightforward. At each temperature, et is computed by the numerical integration of eλ over a wide wavelength range followed by normalization to σT4. The calculations show that et increases with temperature and doping level. At 1300 °K, for a 1‐cm‐thick sample, as the carrier concentration rises from 1016 to 1017 cm−3, et increases fr...
TL;DR: In this article, the surface orientation dependence of the oxidation rate can be explained by orientation dependent of bond density available for reaction with oxygen molecules, which may be attributed to the value for oxygen diffusion through InP oxide.
Abstract: Thermal oxidation of InP and properties of oxide films have been studied. Surface orientation dependence of the oxidation rate can be explained by orientation dependence of bond density available for reaction with oxygen molecules. The activation energy of the parabolic rate constant is 2.06 eV, which may be attributed to the value for oxygen diffusion through InP oxide. From the electron diffraction and infrared absorption measurements, it is found that the oxide film is composed of polycrystalline InPO4 (In2O3+P2O5) and that oxides thermally grown at high temperatures, above 620 °C become In rich and form lower oxides, such as In4O2 and In2O, owing to phosphorus evaporation. Resistivities of the thermally grown oxide films at room temperature range from 108 to 109 Ω cm and decrease with an increase in oxidation temperature and time, which may be mainly caused by lack of P2O5 in the oxide film.
TL;DR: In this paper, a tetragonal distortion of the fcc lattice of γ-iron in a copper matrix has been investigated by X-ray diffraction in the temperature range from 300 to 6 K.
TL;DR: In this paper, resistivity and Hall coefficient have been measured in the temperature range 300-1250 K on samples of n-type epitaxial GaAs from which the substrates have been removed to eliminate substrate conduction at high temperatures.
Abstract: Resistivity and Hall coefficient have been measured in the temperature range 300-1250 K on samples of n -type epitaxial GaAs from which the substrates have been removed to eliminate substrate conduction at high temperatures. These data are useful for determining energy band parameters as well as for modeling epitaxial growth and other high temperature phenomena. The mobilities of electrons in the Γ 6 c minimum and L 6 c minima and the mobility of holes in the Γ 8 v maxima were calculated for the temperature range 300-970 K. From these calculations the mobility in the L 6 c minima was found to decrease faster with increasing temperature than the mobility in the Γ 6 c minimum. Using the temperature dependence of the mobilities, the Γ 6 c − L 6 c − X 6 c ordering of the conduction band minima, and a calculated intrinsic carrier concentration, a self-consistent model for four-band carrier transport was obtained.
TL;DR: In this paper, the kinetics and products of the solid state reaction of titanium thin films and (0001) α-SiC were investigated in the temperature range 844-1073 K using X-ray diffractometry and Auger electron spectroscopy.