A Decrease in the Electrical Resistance of Gold with a Magnetic Field at Low Temperatures

1937 ◽  
Vol 51 (12) ◽  
pp. 1108-1108 ◽  
Author(s):  
W. F. Giauque ◽  
J. W. Stout ◽  
C. W. Clark
Keyword(s):  
Magnetic Field ◽  
Electrical Resistance ◽  
Low Temperatures

scholarly journals The theory of the magneto-resistance effects in metals

1947 ◽  
Vol 190 (1023) ◽  
pp. 435-455 ◽  
Keyword(s):  
Magnetic Field ◽  
Electrical Resistance ◽  
Low Temperatures ◽  
Lorenz Number ◽  
Strong Magnetic Fields ◽  
Pass Through ◽  
Set Up ◽  
Magneto Resistance ◽  
The Magnetic Field ◽  
Overlapping Bands

General formulae are obtained for the effect of a magnetic field on the electrical and thermal conductivities of a metal in which there are two overlapping bands of normal form. Simple formulae are set up which, though not strictly valid for all temperatures and fields, reduce to the correct expressions in the three limiting cases of high temperatures, low temperatures and very strong magnetic fields. The behaviour of the electrical resistance at low temperatures is discussed, and it is shown that in certain cases the resistance may pass through a minimum as the temperature is increased provided the magnetic field is large enough. It is also shown that in general the Lorenz number is increased by the presence of a magnetic field, but that the thermal conductivity of the lattice is unaffected by a magnetic field.

scholarly journals The magneto-resistance effect in cadmium at low temperatures

1937 ◽  
Vol 160 (901) ◽  
pp. 207-229 ◽  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Electrical Resistance ◽  
Low Temperatures ◽  
Linear Part ◽  
Experimental Curve ◽  
Linear Variation ◽  
Experimental Range ◽  
Maximum Field ◽  
Magneto Resistance

The experiments of Kapitza (1929) showed that the increase of electrical resistance produced in a metal by a magnetic field H is not proportional to H 2 , as was previously supposed. In the new experimental range made available by his method (Kapitza 1927) of producing very strong fields up to 300 kilogauss, Kapitza found that the increase of resistance tended towards a linear variation with the field strength. The result may be expressed in the formula ΔR / R 0 = b ( H - H k ), for H ≫ H k , where R 0 is the resistance at 0° C. This gives the asymptote to the experimental curve: but if experiments are made at field strengths up to a maximum H m , and H m ≫ H k , then over a large part of the experimental range the curve obtained is practically identical with the asymptote. If the linear part of the curve is then extrapolated back to meet the axis of H , its intercept on that axis gives the parameter H k , and the slope of the line gives the parameter b . If, however, the maximum field used is only of the order of H k , the linear variation is only reached outside the experimental range; and some formula must be employed, in effect, to extrapolate to the region where the linear law holds, before the position of the asymptote and the values of the parameters can be derived. It is obvious that the values so obtained will vary according to the particular formula adopted.

MAGNETIC FIELD DEPENDENT RELAXATION TIME IN p-InSb AT LOW TEMPERATURES

1981 ◽  
Vol 42 (C5) ◽  
pp. C5-689-C5-693
Author(s):  
J. D.N. Cheeke ◽  
G. Madore ◽  
A. Hikata
Keyword(s):  
Magnetic Field ◽  
Relaxation Time ◽  
Low Temperatures ◽  
Field Dependent

Simple Systems

2017 ◽  
Author(s):  
Jochen Rau
Keyword(s):  
Magnetic Field ◽  
Low Temperatures ◽  
General Framework ◽  
Gibbs State ◽  
Macroscopic System ◽  
Basic Model ◽  
System A ◽  
Paramagnetic Salt ◽  
High And Low Temperatures ◽  
Simple Systems

Even though the general framework of statistical mechanics is ultimately targeted at the description of macroscopic systems, it is illustrative to apply it first to some simple systems: a harmonic oscillator, a rotor, and a spin in a magnetic field. These applications serve to illustrate how a key function associated with the Gibbs state, the so-called partition function, is calculated in practice, how the entropy function is obtained via a Legendre transformation, and how such systems behave in the limits of high and low temperatures. After discussing these simple systems, this chapter considers a first example where multiple constituents are assembled into a macroscopic system: a basic model of a paramagnetic salt. It also investigates the size of energy fluctuations and how—in the case of the paramagnet—these fluctuations scale with the number of constituents.

scholarly journals Review of Multi-Physics Modeling on the Active Magnetic Regenerative Refrigeration

2021 ◽  
Vol 26 (2) ◽  
pp. 47
Author(s):  
Julien Eustache ◽  
Antony Plait ◽  
Frédéric Dubas ◽  
Raynal Glises
Keyword(s):  
Magnetic Field ◽  
Low Temperatures ◽  
Room Temperature ◽  
State Of The Art ◽  
Vapor Compression ◽  
Crucial Step ◽  
Potential Alternative ◽  
Vapor Compression Refrigeration ◽  
Preliminary Study ◽  
Physics Modeling

Compared to conventional vapor-compression refrigeration systems, magnetic refrigeration is a promising and potential alternative technology. The magnetocaloric effect (MCE) is used to produce heat and cold sources through a magnetocaloric material (MCM). The material is submitted to a magnetic field with active magnetic regenerative refrigeration (AMRR) cycles. Initially, this effect was widely used for cryogenic applications to achieve very low temperatures. However, this technology must be improved to replace vapor-compression devices operating around room temperature. Therefore, over the last 30 years, a lot of studies have been done to obtain more efficient devices. Thus, the modeling is a crucial step to perform a preliminary study and optimization. In this paper, after a large introduction on MCE research, a state-of-the-art of multi-physics modeling on the AMRR cycle modeling is made. To end this paper, a suggestion of innovative and advanced modeling solutions to study magnetocaloric regenerator is described.

LOW-TEMPERATURE NORMAL-STATE HALL EFFECT IN HIGH-TcBi2Sr2-xLaxCuO6+δ REVEALED BY 60 T MAGNETIC FIELDS

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3171-3174
Author(s):  
F. F. BALAKIREV ◽  
J. B. BETTS ◽  
G. S. BOEBINGER ◽  
S. ONO ◽  
Y. ANDO ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Low Temperature ◽  
Carrier Concentration ◽  
Hall Coefficient ◽  
Normal State ◽  
Ground State ◽  
Low Temperatures ◽  
Optimal Doping ◽  
Underdoped Sample ◽  
Additional Support

We report low-temperature Hall coefficient in the normal state of the high-Tc superconductor Bi 2 Sr 2-x La x CuO 6+δ. The Hall coefficient was measured down to 0.5 K by suppressing superconductivity with a 60 T pulsed magnetic field. The carrier concentration was varied from overdoped to underdoped regimes by partially substituting Sr with La in a set of five samples. The observed saturation of the Hall coefficient at low temperatures suggests the ability to extract the carrier concentration of each sample. The most underdoped sample exhibits a diverging Hall coefficient at low temperatures, consistent with a depletion of carriers in the insulating ground state. The Hall number exhibits a sharp peak providing additional support for the existence of a phase boundary at the optimal doping.

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