Springer Online Journal Archives 1860-2000
The two-band model proposed by Suhl, Matthias, and Walker for pure transition metal superconductors is extended to transition metals with paramagnetic impurities under the assumption that the cutoff parameters Ω ij (i, j = s, d) of the pairing interactions between electrons V ij are different from each other. An equation is derived for the critical temperature T c .In the dilute limit T c (n) can increase with impurity concentration n only for Ω ss ≠ Ω sd , Ω dd ≠ Ω sd . In the one-band limit the results reduce to those of Abrikosov and Gor' kov. The theoretical function T c (n) is used to fit the experimental data for the alloys La 1 − n Ce n and Ce 1 − n Nd n Ru2. The agreement of the theoretical T c (n) curve with the experimental points is good, with the exception of La 1 − n Ce n for values n near the critical concentration n c ,where stronger deviations appear as a consequence of magnetic ordering.
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