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.

Out-of-Plane and in-Plane Conduction in Insulating and Strongly Underdoped Cuprates

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3203-3206
Author(s):  
C. C. Almasan ◽  
G. A. Levin ◽  
E. Cimpoiasu ◽  
T. Stein ◽  
D. A. Gajewski ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Normal State ◽  
Low Temperatures ◽  
Elementary Step ◽  
Charge Carriers ◽  
Two Dimensional ◽  
Out Of Plane ◽  
Underdoped Cuprates

We report measurements of out-of-plane (ρ c ) and in-plane (ρab) normal-state resistivities of single crystals of insulating PrBa2Cu3O 7-δ and strongly underdoped oxygen deficient YBa2Cu3O 6.41 using a flux transformer method. In the superconducting specimens, the onset of superconductivity was suppressed by a magnetic field of 9 T. We have found that the anisotropy ρc/ρab of these samples increases monotonically at low temperatures with no signs of saturation. The temperature dependence of ρc/ρab for YBa2Cu3O6.41 is well described by ρc/ρab=a +bT-2/3, but over a smaller temperature range than for insulating PrBa2Cu3O 7-δ. Both the absence of saturation of ρc/ρab and its T-2/3 dependence indicate two-dimensional conduction. This means that the average in-plane hopping distance of the localized charge carriers increases with decreasing T according to Mott's [Formula: see text] law, while the elementary step in the c-direction remains T independent, equal to the spacing between the bilayers.

Variation of the temperature dependence of the energy-relaxation time with magnetic field in open quantum dot arrays at low temperatures

2002 ◽  
Vol 314 (1-4) ◽  
pp. 486-489 ◽  
Author(s):  
C. Prasad ◽  
D.K. Ferry ◽  
A. Shailos ◽  
M. Elhassan ◽  
J.P. Bird ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Relaxation Time ◽  
Quantum Dot ◽  
Temperature Dependence ◽  
Low Temperatures ◽  
Energy Relaxation ◽  
Open Quantum ◽  
Energy Relaxation Time

Doping dependence of the diffusivity-mobility ratio in semiconductors in the presence of a large magnetic field

1972 ◽  
Vol 40 (2) ◽  
pp. 113-114 ◽  
Author(s):  
A.N. Chakravarti ◽  
D.P. Parui
Keyword(s):  
Magnetic Field ◽  
Mobility Ratio ◽  
Doping Dependence ◽  
Large Magnetic Field

MAGNETIZATION STUDIES OF Rb3C60 IN SUPERCONDUCTING STATE

1993 ◽  
Vol 07 (11) ◽  
pp. 2163-2176 ◽  
Author(s):  
C. POLITIS ◽  
V. BUNTAR ◽  
V.P. SEMINOZHENKO
Keyword(s):  
Magnetic Field ◽  
Temperature Dependence ◽  
Critical Current ◽  
Magnetic Measurements ◽  
Landau Theory ◽  
Critical Magnetic Field ◽  
Zero Temperature ◽  
Ginzburg Landau ◽  
Different Temperatures ◽  
Increasing Temperature

We present the results of magnetic measurements in fields up to 50 kOe for superconducting Rb 3 C 60. The temperature dependence of upper H c 2 critical magnetic field is determined, from which the zero temperature value Hc2(0)=465±50 kOe is evaluated. The magnitudes of penetration depth and coherence length are calculated as ξ(0)=26.7±3 Å; λ L (0)=2150±100 Å at zero temperature. The temperature dependence of ξ(T) and λ L (T) for T≧23 K is in good agreement with the Ginzburg-Landau theory. The critical current densities for different temperatures are calculated, showing a strong decrease of Jc with increasing temperature for T≤7 K . Two regions of fading critical current density on a magnetic field dependence are found.

SUPPRESSION OF BACKSCATTERING IN QUANTUM HALL NARROW CHANNEL UNDER TRANSVERSALLY MODULATED MAGNETIC FIELD

2004 ◽  
Vol 18 (27n29) ◽  
pp. 3563-3568
Author(s):  
MASAHIRO HARA ◽  
AKIRA ENDO ◽  
SHINGO KATSUMOTO ◽  
YASUHIRO IYE
Keyword(s):  
Magnetic Field ◽  
Temperature Dependence ◽  
Quantum Hall ◽  
Narrow Channel ◽  
Directed Edge ◽  
Thermally Activated ◽  
Quantum Hall Regime ◽  
Hall Regime ◽  
Back Scattering ◽  
Increasing Temperature

We have studied transport in a narrow Hall bar subjected to a transversally modulated magnetic field in quantum Hall regime. Landau level spatially varies across the channel and suppresses back scattering between oppositely directed edge channels. The resistance suppressed by the "magnetic barrier" recovers with increasing temperature, showing thermally activated temperature dependence.

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