THERMOELECTRICITY AND ELECTRICAL RESISTIVITY OF DILUTE COPPER ALLOYS OF CHROMIUM, MANGANESE, IRON, AND COBALT AT LOW TEMPERATURES

1962 ◽  
Vol 40 (1) ◽  
pp. 98-112 ◽  
Author(s):  
A. Kjekshus ◽  
W. B. Pearson

Low-temperature thermoelectric and electrical resistivity measurements on dilute copper alloys with Cr, Mn, Fe, or Co are reported and discussed, particularly in relation to similar measurements on gold alloys. Both thermoelectric and resistivity measurements have been made for the first time on the same alloys. This paper is a sequel to an earlier paper where the thermoelectric power of "pure" copper was analyzed.

1978 ◽  
Vol 38 (6) ◽  
pp. 567-573 ◽  
Author(s):  
A. M. Guénault ◽  
N. S. Lawson ◽  
J. Northfield

1897 ◽  
Vol 60 (359-367) ◽  
pp. 425-432 ◽  

In a previous communication to the Royal Society we have pointed out the behaviour of electrolytically prepared bismuth when cooled to very low temperatures, and at the same time subjected to transverse magnetisation. During the last summer we have extended these observations, and completed them, as far as possible, by making measurements of the electrical resistance of a wire of pure bismuth, placed transversely to the direction of the field of an electromagnet, and at the same time subjected to the low temperature obtained by the use of liquid air. Sir David Salomons was so kind as to lend us for some time his large electromagnet, which, in addition to giving a powerful field, is provided with the means of easily altering the interpolar distance of the pole pieces, and also for changing from one form of pole piece to another.


1999 ◽  
Vol 13 (29n31) ◽  
pp. 3786-3791 ◽  
Author(s):  
R. CAURO ◽  
J. C. GRENET ◽  
A. GILABERT ◽  
M. G. MEDICI

We report, for the first time, experiments of persistent photoconductivity (PPC) in thin films of manganese perovskites La 0.7 Ca 0.25 Ba 0.05 MnO 3 and La 0.7 Ca 0.2 Ba 0.1 MnO 3 showing a persistent decrease of a few percent of the resistance after illumination with visible light. These persistent photoinduced effects are seen only in a range of low temperatures (<25 K) well below the insulator-metal transition at respectively T c=173 K and T c=120 K. In this low temperature range, the transport mechanism is rather of activated hopping type regime.


2015 ◽  
Vol 29 (27) ◽  
pp. 1550189
Author(s):  
Q. R. Hou ◽  
B. F. Gu ◽  
Y. B. Chen

In this paper, we report a large enhancement in the thermoelectric power factor in CrSi2 film via Si:B (1 at.% B content) addition. The Si:B-enriched CrSi2 films are prepared by co-sputtering CrSi2 and heavily B-doped Si targets. Both X-ray diffraction patterns and Raman spectra confirm the formation of the crystalline phase CrSi2. Raman spectra also indicate the crystallization of the added Si:B. With the addition of Si:B, the electrical resistivity [Formula: see text] decreases especially at low temperatures while the Seebeck coefficient [Formula: see text] increases above 533 K. As a result, the thermoelectric power factor, [Formula: see text], is greatly enhanced and can reach [Formula: see text] at 583 K, which is much larger than that of the pure CrSi2 film.


2007 ◽  
Vol 556-557 ◽  
pp. 367-370 ◽  
Author(s):  
Michael Krieger ◽  
Kurt Semmelroth ◽  
Heiko B. Weber ◽  
Gerhard Pensl ◽  
Martin Rambach ◽  
...  

We report on admittance spectroscopy (AS) investigations taken on aluminum (Al)- doped 6H-SiC crystals at low temperatures. Admittance spectra taken on Schottky contacts of highly doped samples (NA ≥ 7.2×1017 cm-3) reveal two series of conductance peaks, which cause two different slopes of the Arrhenius plot. The steep slope is attributed to the Al acceptor, while the flatter one - obtained from the low temperature peaks - is attributed to the activation energy ε3 of nearest neighbor hopping. We propose a model, which explains the unexpected sharpness of the low temperature conductance peaks and the disappearance of these peaks for low acceptor concentrations. The model is verified by simulation, and the AS results are compared with corresponding results obtained from resistivity measurements taken on 4H- and the identical 6HSiC samples.


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