Effect of a magnetic field on the dynamics of dislocations in normal metals with a high impurity concentration at low temperatures

2008 ◽  
Vol 34 (9) ◽  
pp. 768-770 ◽  
Author(s):  
B. B. Malashenko
2013 ◽  
Vol 205-206 ◽  
pp. 271-277 ◽  
Author(s):  
Maria Luisa Polignano ◽  
Isabella Mica ◽  
Elena Cazzini ◽  
Monica Ceresoli ◽  
Davide Codegoni ◽  
...  

In this paper, we test proximity gettering layers obtained by carbon or silicon implantation for their efficiency in molybdenum and tungsten gettering. DLTS was used to measure the impurity concentration in the solid solution and so to evaluate gettering efficiency. It was found that carbon implantation is effective in capturing these impurities, whereas silicon implantation is not. Extended defects seem not to play an important role in gettering these impurities. In addition, gettering was found to be most effective at high impurity concentration.


1981 ◽  
Vol 9 (4) ◽  
pp. 434-438
Author(s):  
Kouichi MURAKAMI ◽  
Eiji IKAWA ◽  
A.H. ORABY ◽  
Kenji GAMO ◽  
Susumu NAMBA ◽  
...  

1981 ◽  
Vol 42 (C5) ◽  
pp. C5-689-C5-693
Author(s):  
J. D.N. Cheeke ◽  
G. Madore ◽  
A. Hikata

Author(s):  
Jochen Rau

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.


2021 ◽  
Vol 26 (2) ◽  
pp. 47
Author(s):  
Julien Eustache ◽  
Antony Plait ◽  
Frédéric Dubas ◽  
Raynal Glises

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.


The theory developed in II is extended to cover the case of a superconductor, and a formula is derived relating the r. f. resistivity to the superconducting penetration depth and other parameters of the metal. It is shown how the penetration depth may be deduced directly from measurements of the skin reactance, and a method of measuring reactance is described, based essentially on the variation of the velocity of propagation along a transmission line due to the reactance of the conductors. For technical reasons it is not convenient to measure the reactance absolutely, but a simple extension of the technique described in I enables the change in reactance to be accurately measured when superconductivity is destroyed by a magnetic field. The method has been applied to mercury and tin. In the former case the results are in agreement with Shoenberg’s direct measurements, and confirm that the penetration depth at 0° K is of the order of 7 x 10 –6 cm. The theory developed at the beginning of the paper is used to deduce the variation of penetration depth with temperature from the resistivity measurements of I, and it is shown that agreement with other determinations and with the reactance measurements is fairly good, but not perfect. Some of the assumptions used in developing the theory are critically discussed, and a qualitative account is given to show how Heisenberg’s theory of superconductivity offers an explanation of some of the salient features of superconductivity and inparticular indicates the relation between superconducting and normal electrons.


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