Kondo behavior of inG. A. Wigger1, E. Felder1, S. Weyeneth1, H. R. Ott1 and Z. Fisk2
1 Laboratorium für Festkörperphysik, ETH-Hönggerberg - CH-8093 Zürich, Switzerland
2 Department of Physics, University of California - Davis, CA 95616, USA
received 6 July 2004; accepted in final form 30 September 2004
published online 29 October 2004
Replacing for in semiconducting at the few at.% level induces metallic behaviour and Kondo-type phenomena at low temperatures, a rather unusual feature for impurities in metallic hosts. For , the resistance minimum occurs at T=17 . The subsequent characteristic logarithmic increase of the resistivity with decreasing temperature merges into the expected T2-dependence below 0.8 . Data of the low-temperature specific heat and the magnetization are analyzed by employing a simple resonance-level model. Analogous measurements on with a small amount of revealed no traces of Kondo behavior, above 0.4 .
72.15.Qm - Scattering mechanisms and Kondo effect.
75.20.Hr - Local moment in compounds and alloys; Kondo effect, valence fluctuations, heavy fermions.
75.30.Mb - Valence fluctuation, Kondo lattice, and heavy-fermion phenomena.
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