Studies of ion/molecule reactions, ion mobilities, and their temperature dependence to very low temperatures using a liquid-helium-cooled ion drift tube

1983 ◽  
Vol 49 (1) ◽  
pp. 61-83 ◽  
Author(s):  
H. Böhringer ◽  
F. Arnold
Keyword(s):  
Temperature Dependence ◽  
Liquid Helium ◽  
Low Temperatures ◽  
Drift Tube ◽  
Ion Drift ◽  
Ion Molecule Reactions

Resistivity of plutonium, neptunium and uranium due to the accumulation of radioactive self damage

1965 ◽  
Vol 284 (1398) ◽  
pp. 325-343 ◽  
Keyword(s):  
Crystal Structure ◽  
Temperature Dependence ◽  
Liquid Helium ◽  
Low Temperatures ◽  
Liquid Helium Temperature ◽  
Helium Temperature ◽  
Additive Resistance

An increase with time in resistivity occurs in plutonium at low temperatures as a result of radioactive self damage. The effect has been studied in experiments at liquid helium temperature lasting over 8000h and has been found to exist in the α , β and δ phases of the metal. In all cases the resistivity approaches saturation, the rates of increase depending on the crystal structure and isotropic content of the sample. In spite of wide differences in these rates the functional increase is roughly the same. The temperature dependence of the accumulated resistivities in all three modifications deviates very strongly from a simple additive resistance obeying Matthiesen’s rule. The resistivity of fully damaged α plutonium is almost temperature independent, becoming smaller than that of the undamaged specimen above about 50 °K. Measurements on neptunium and uranium 233 have also shown resistivity increases with time at helium temperatures, but the effect is too small to decide whether Matthiesen’s rule is obeyed in these metals. The observed effects have been discussed under the assumption that in plutonium scattering of electrons at low temperatures is mainly due to a co-operative phenomenon.

TEMPERATURE DEPENDENCE BEHAVIOR OF ELECTRICAL RESISTIVITY IN NOBLE METALS AT LOW TEMPERATURES

2014 ◽  
Vol 5 (3) ◽  
pp. 982-992 ◽  
Author(s):  
M AL-Jalali
Keyword(s):  
Experimental Data ◽  
Electrical Resistivity ◽  
Temperature Dependence ◽  
Concentration Dependence ◽  
Low Temperatures ◽  
Noble Metals ◽  
Phonon Scattering ◽  
Theoretical Models ◽  
Residual Resistivity ◽  
Electron Phonon Scattering

Resistivity temperature – dependence and residual resistivity concentration-dependence in pure noble metals(Cu, Ag, Au) have been studied at low temperatures. Dominations of electron – dislocation and impurity, electron-electron, and electron-phonon scattering were analyzed, contribution of these mechanisms to resistivity were discussed, taking into consideration existing theoretical models and available experimental data, where some new results and ideas were investigated.

93Nb Nuclear Spin-Spin Relaxation in the Low-Dimensional Antiferromagnet Fe0.25NbS2

2007 ◽  
Vol 62 (10-11) ◽  
pp. 627-632
Author(s):  
Noriaki Okubo
Keyword(s):  
Temperature Dependence ◽  
Spin Relaxation ◽  
Nuclear Spin ◽  
Low Temperatures ◽  
Fast Decay ◽  
Low Dimensional

93Nb nuclear spin-spin relaxation has been examined in the low-dimensional antiferromagnet Fe0.25NbS2 between 4.2 K and 300 K. The relaxation is characterized by two T2’s. The temperature dependence is discussed together with the origin of the disappearance of the fast decay at low temperatures.

scholarly journals Experiments at very low temperatures obtained by the magnetic method I—The production of the low temperatures

1935 ◽  
Vol 149 (866) ◽  
pp. 152-176 ◽  
Keyword(s):  
Liquid Helium ◽  
Vapour Pressure ◽  
Low Temperatures ◽  
Usual Method ◽  
Magnetic Method ◽  
Isothermal Magnetization

The lowest limit of temperature obtainable by the hitherto usual method of evaporating liquid helium lies at about 0⋅7º. At this temperature the vapour pressure of helium is already so small that it does not seem possible to proceed to appreciably lower temperatures in this way. In the course of last year the first successful experiments in attaining still lower temperatures were carried out using the magnetic method proposed by Debye and Giauque. This method is based on the possibility of diminishing considerably the entropy of some paramagnetic salts by isothermal magnetization. The subsequent demagnetization, if carried out adiabatically, then results in a lowering of the temperature.

Temperature Dependence of the Diffusivity–Mobility Ratio in Degenerate Semiconductors in the Presence of a Large Magnetic Field

1973 ◽  
Vol 51 (4) ◽  
pp. 491-492 ◽  
Author(s):  
A. N. Chakravarti ◽  
D. P. Parui
Keyword(s):  
Magnetic Field ◽  
Temperature Dependence ◽  
Low Temperatures ◽  
Mobility Ratio ◽  
Degenerate Semiconductors ◽  
Large Magnetic Field ◽  
Increasing Temperature

The diffusivity–mobility ratio in degenerate semiconductors in the presence of a large magnetic field is found to increase with increasing temperature at a rate which is dependent on temperature at relatively low temperatures. It is also found that, at any given temperature, the ratio is increased by the application of the field.

scholarly journals Martensitic transformation in the systems based on Fe-Ni compositions in strong pulsed magnetic fields

2021 ◽  
pp. 22-29 ◽  
Author(s):  
I. Zolotarevskii
Keyword(s):  
Magnetic Field ◽  
Martensitic Transformation ◽  
Magnetic Fields ◽  
Temperature Dependence ◽  
Strong Magnetic Field ◽  
Low Temperatures ◽  
Strong Dependence ◽  
Magnetic Interaction ◽  
Iron Alloys ◽  
Pulsed Magnetic Fields

Purpose of work. To ascertain the causes of the abnormally large displacement of the martensitic point in steels and iron alloys in strong pulsed magnetic fields at low temperatures. Research methods. Generalization of experimental and theoretical investigations of the strong magnetic field influence on the martensitic transformation in steels and iron alloys, taking into account the magnetic state of austenite. The obtained results. The distributions of the martensitic point displacement ΔMS from the content of the main component - iron and the temperature of the martensitic γ → α- transformation beginning (martensitic point MS) in different experiments are obtained. It is shown that the obtained temperature dependence ΔMS(MS) in a strong magnetic field at low temperatures decomposes into two components, one of which correlates with the generalized Clapeyron-Clausius equations, and the other is opposite to it. In addition, it was found that steels and alloys with intense γ → α- transformation in a magnetic field contain at least 72.5% iron (wt), which at low temperatures in the fcc structure is antiferromagnetic. Scientific novelty. The anomalous temperature dependence of the distribution ΔMS(MS) in a strong magnetic field is explained on the basis of quantum representations of the magnetic interaction of atoms in the Fe-Ni system. This effect is associated with a number of other invar effects, in particular, with an abnormally large spontaneous and forced magnetostriction, a strong dependence of the resulting exchange integral on the interatomic distance. The point of view according to which in these alloys in a magnetic field γ → α- transformation occurs by the type of “magnetic first kind phase transformation” is substantiated. It is assumed that the nucleation of the martensitic phase in a magnetic field occurs in (at) local regions of γ- phase with disoriented atomic magnetic moments (with high compression and increased forced magnetostriction). Practical value. The information obtained in this work provides grounds for explaining the kinetic features of the transformation of austenite into martensite in steels and iron alloys.

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