Specific Heat of Superconducting Transition Metals Containing Nonmagnetic Impurities at Low Temperatures

1971 ◽  
Vol 3 (3) ◽  
pp. 779-784 ◽  
Author(s):  
Richard H. Burkel ◽  
W. S. Chow
1965 ◽  
Vol 19 (2) ◽  
pp. 101-102 ◽  
Author(s):  
C.C. Sung ◽  
L. Yun Lung Shen

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hansong Zeng ◽  
Dan Zhou ◽  
Guoqing Liang ◽  
Rujun Tang ◽  
Zhi H. Hang ◽  
...  

AbstractKondo effect is an interesting phenomenon in quantum many-body physics. Niobium (Nb) is a conventional superconductor important for many superconducting device applications. It was long thought that the Kondo effect cannot be observed in Nb because the magnetic moment of a magnetic impurity, e.g. iron (Fe), would have been quenched in Nb. Here we report an observation of the Kondo effect in a Nb thin film structure. We found that by co-annealing Nb films with Fe in Argon gas at above 400 $$^{\circ }$$ ∘ C for an hour, one can induce a Kondo effect in Nb. The Kondo effect is more pronounced at higher annealing temperature. The temperature dependence of the resistance suggests existence of remnant superconductivity at low temperatures even though the system never becomes superconducting. We find that the Hamann theory for the Kondo resistivity gives a satisfactory fitting to the result. The Hamann analysis gives a Kondo temperature for this Nb–Fe system at $$\sim $$ ∼ 16 K, well above the superconducting transition onset temperature 9 K of the starting Nb film, suggesting that the screening of the impurity spins is effective to allow Cooper pairs to form at low temperatures. We suggest that the mechanism by which the Fe impurities retain partially their magnetic moment is that they are located at the grain boundaries, not fully dissolved into the bcc lattice of Nb.


1978 ◽  
Vol 56 (10) ◽  
pp. 1390-1394
Author(s):  
K. P. Srivastava

An extensive numerical study on specific heat at constant volume (Cv) for ordered and isotopically disordered lattices has been made. Cv at various temperatures for ordered and disordered linear and two-dimensional lattices have been compared and no appreciable difference in Cv between these two structures has been observed. Effect of concentration of light atoms on Cv for three-dimensional isotopically disordered lattices has also been shown.In spite of taking next-nearest-neighbour interaction into account, no substantial change in Cv between the ordered and isotopically disordered linear lattices has been found. It is shown that the low lying modes contribute substantially at low temperatures.


1987 ◽  
Vol 99 ◽  
Author(s):  
B. Stritzker ◽  
W. Zander ◽  
F. Dworschak ◽  
U. Poppe ◽  
K. Fischer

ABSTRACTBulk samples of YBa2Cu3O7−x have been homogenously irradiated with 3 MeV electrons at temperatures below 20 K. Whereas the superconducting transition temperature, Tc, drops dramatically with increasing dose the width of the transition remains unchanged (Δ Tc ≤ 1.5 K). The normal state resistance at 100 K increases substantially during the electron irradiation. Several irreproducible experiments can be interpreted with a radiation induced, unstable increase of Tc.


1979 ◽  
Vol 13 (7) ◽  
pp. 573-575 ◽  
Author(s):  
Hiroaki Wada ◽  
Koshiro Sakamoto

1996 ◽  
Vol 97 (3) ◽  
pp. 175-178 ◽  
Author(s):  
E.B. Nyeanchi ◽  
D.F. Brewer ◽  
T.E. Hargreaves ◽  
N.E. Hussey ◽  
A.L. Thomson ◽  
...  

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