Au Temperature Research Articles

Electron-Phonon Coupling Parameter of Ferromagnetic Metal Fe and Co.

The electron-phonon coupling (g) parameter plays a critical role in the ultrafast transport of heat, charge, and spin in metallic materials. However, the exact determination of the g parameter is challenging because of the complicated process during the non-equilibrium state. In this study, we investigate the g parameters of ferromagnetic 3d transition metal (FM) layers, Fe and Co, using time-domain thermoreflectance. We measure a transient increase in temperature of Au in an FM/Au bilayer; the Au layer efficiently detects the strong heat flow during the non-equilibrium between electrons and phonons in FM. The g parameter of the FM is determined by analyzing the temperature dynamics using thermal circuit modeling. The determined g values are 8.8–9.4 × 1017 W m−3 K−1 for Fe and 9.6–12.2 × 1017 W m−3 K−1 for Co. Our results demonstrate that all 3d transition FMs have a similar g value, in the order of 1018 W m−3 K−1.

Au Fixed Point Development at NRC

Two Au fixed points filled using metal of different nominal purities in carbon crucibles have been developed at the National Research Council Canada (NRC). The primary motivation behind this project was to provide the means for direct thermocouple calibrations at the Au freezing point (\(1064.18~^\circ \hbox {C}\)). Using a Au fixed point filled with the metal of maximum available purity [99.9997 % pure according to glow discharge mass spectroscopy (GDMS)], multiple freezing plateaus were measured in a commercial high-temperature furnace. Four Pt/Pd thermocouples constructed and calibrated in-house were used to measure the freezing plateaus. From the calibration at Sn, Zn, Al and Ag fixed points, the linear deviation function from the NIST-IMGC reference function (IEC 62460:2008 Standard) was determined and extrapolated to the freezing temperature of Au. For all the Pt/Pd thermocouples used in this study, the measured EMF values agree with the extrapolated values within expanded uncertainty, thus substantiating the use of 99.9997 % pure Au fixed point cell for thermocouple calibrations at NRC. Using the Au fixed point filled with metal of lower purity (99.99 % pure according to GDMS), the effect of impurities on the Au freezing temperature measured with Pt/Pd thermocouple was further investigated.

Effects of the formation temperature of Au + Ga solid solution droplets on the growth behaviors of GaN nanowires on Si(111) by using MOCVD

Effects of the formation temperature of Au + Ga solid solution droplets on the growth behaviors of GaN nanowires on Si(111) by using MOCVD

Temperature-dependent secondary electron yield from ion bombardment of gold and copper oxide superconductors.

First measurements on the ion-induced kinetic secondary-electron emission have been performed with low beam current densities in the low target temperature range $70 \mathrm{K}lTl300 \mathrm{K}$ under good vacuum conditions ($p\ensuremath{\approx}5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$ Pa) from sputter-cleaned Au foils (1000 \AA{}) and from Y${\mathrm{Ba}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$. The secondary-electron yield $\ensuremath{\gamma}$ decreases with decreasing temperature of Au and Y${\mathrm{Ba}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$ targets. This is in contrast to the expectations based on previous experiments and theoretical considerations. In the case of Y${\mathrm{Ba}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$, a strong enhancement of $\ensuremath{\gamma}$ below the superconducting transition temperature ${T}_{c}$ is observed.

The Spin Glass State and the Kondo Effect in Dilute Au(Cr), Au(Mn) and Au(Fe) Alloys Studied by Nuclear Orientation of 54Mn

The nuclear orientation experiment on 54 Mn nuclei in Au metal and Au(Cr), Au(Mn), and Au(Fe) alloys have been made to study the nature of the spin glass and the Kondo effect in these alloys. Concentrations of impurities in the alloys were between 5 and 500 at. ppm and measurements were performed in the temperature range between 7 and 8 mK. Gamma-ray anisotropy from oriented 54 Mn in the Au(Mn) and Au(Cr) alloys can be explained by the 3-dimensional Lorentzian distribution function, when the molecular field approximation is applied to the spin glass state. For the Au(Fe) alloys, however, widths of the distribution function are less than those expected from the molecular field approximation, which may be attributed to the Kondo effect. Nuclear orientation of 54 Mn in Au metal is explained by the slow relaxation model with S Mn =5/2. This indicates that the Kondo temperature of Au(Mn) is lower than 7 mK.

Microstructure and phase stability of INCONEL alloy 617

INCONEL alloy 617 (54 Ni, 22 Cr, 12.5 Co, 9 Mo, 1 Al, 0.07 C) is a solid-solution alloy with good corrosion resistance and an exceptional combination of high-temperature strength and oxidation resistance. A laboratory study was performed to determine the effects of long-time (215 to over 10,000 h) exposure to temperatures up to 2000°F (1093°C) on the microstructure and phase stability of the alloy. To investigate the strengthening response exhibited by the alloy during high-temperature exposure, microstructures were correlated with mechanical properties. The major phase present in the alloy after exposure to all temperatures from 1200 to 2000°F (649 to 1093°C) was found to be M23C6. The phase precipitated as discrete particles and remained stable at au temperatures. No MC or M6C carbides were found. A small amount of gamma prime was found in samples exposed at 1200°F (649°C) and 1400°F (760°C). A PHACOMP analysis indicated 0.63 pct gamma prime could form. No topological close-packed phases such as sigma, mu, and chi were found. Strengthening of the alloy during exposure to temperature was found to result primarily from the precipitation of M23C6. The phase provides effective strengthening because it precipitates in discrete particles and remains stable at temperatures to 2000°F (1093°C). The amount of gamma prime formed is not sufficient to cause appreciable hardening, but it does provide some strengthening at 1200 to 1400°F (649 to 760°C).

Pressure-Induced Electron Transition in AuGa2

We report measurements of a large, nearly discontinuous change in the superconducting transition temperature of Au${\mathrm{Ga}}_{2}$ near 6 kbar as predicted earlier from pressure measurements of cross-sectional areas of the Fermi surface. This is interpreted as strong evidence for a pressure-induced electron transition near 6 kbar at liquid-He temperatures.

Glycogenolysis in the Liver of the Common Frog, Rana Temporaria

ABSTRACT The form of the temperature-glycogenolysis curve of frog’s fiver slices, when incubated with Ringer solution, was determined over the range 7-21° C. for samples of frogs over a period of 18 months. Three types of curve were observed: (a) Low linear, interpreted as being the least complex form, in which the action of temperature is not complicated by other factors.(b) Type B, which showed a disproportionate increase in glucose production above a certain temperature, attributed to the potentiation of sympathomimetic material.(c) High linear. Both the addition of adrenaline and noradrenaline to the incubation medium caused an increase in glucose production at all temperatures. Also, the dispropor-tionate increase in glucose production of the type B curve occurred at a lower temperature in the presence of either of these agents. Thyroxine had no effect on the form of the temperature-glycogenolysis curve, and there was no correlation between the state of activity of the thyroid gland and the type of temperature-glycogenolysis curve. Glucose production of Ever slices was lowered at all temperatures by the in vivo administration of insulin 19 hr. prior to an experiment. Insulin in vitro had no action. Dibenzyline lowered glucose production of Ever sEces at aU temperatures, and raised the temperature at which the extra glucose production, associated with a type B curve, occurred. The extrapolation of the lower portion of the mean curve after dibenzyline to 210 C. gave a line almost identical with the mean low linear curve. The environmental temperature at which frogs were maintained prior to an experiment did not affect the form of the temperature-glycogenolysis curve. The seasonal variation in Ever-glycogen content was found to agree closely with the values obtained by Smith (1950).