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Anomalous Behavior of the Kondo Superconductor (La1−xCex) Al2

  • G. V. Minnigerode
  • H. Armbrüster
  • G. Riblet
  • F. Steglich
  • K. Winzer

Abstract

At low temperatures two phenomena of collective behavior of the conduction electrons in metals are known: superconductivity and the Kondo effect. With the system (La, Ce) Al2 we succeeded in demonstrating a strong interaction between these two phenomena as predicted by Müller-Hartmann and Zittartz in 1971.1 The most unusual behavior of this superconducting alloy is the vanishing of superconductivity below a second transition temperature at very low temperatures. This second transition back into the normal state was first observed by Riblet and Winzer2 in an adiabatic demagnetization cryostat with a standard ac mutual inductance technique. Figure 1 shows a typical example of these two transitions. The induction signal of the specimen compared to that of a clean LaAl2 probe of the same size is plotted vs. temperature. This specimen with 0.67 at. % Ce substitution of La in LaAl2 becomes superconducting between 1.5 and 1°K and normal again below 0.5°K. As a consequence of this second transition, the temperature dependence of all the other superconducting properties becomes strange. It is therefore proposed to call such an alloy a “Kondo superconductor.”

Keywords

Critical Magnetic Field Kondo Effect Impurity Spin Kondo System Specific Heat Jump 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

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    E. Müller-Hartmann and J. Zittartz, Phys. Rev. Lett. 26, 428 (1971).ADSCrossRefGoogle Scholar
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Copyright information

© Plenum Press, New York 1974

Authors and Affiliations

  • G. V. Minnigerode
    • 1
  • H. Armbrüster
    • 1
  • G. Riblet
    • 1
  • F. Steglich
    • 1
  • K. Winzer
    • 1
  1. 1.Physics InstituteUniversity of CologneGermany

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