Kondo Behavior of U in CaB$_6$

G. A. Wigger; E. Felder; S. Weyeneth; H. R. Ott; Z. Fisk

doi:10.1016/j.physb.2005.01.269

paper

Kondo Behavior of U in CaB $_{6}$

arXiv:cond-mat/0407158 · doi:10.1016/j.physb.2005.01.269

Abstract

Replacing U for Ca in semiconducting CaB $_{6}$ at the few at.% level induces metallic behaviour and Kondo-type phenomena at low temperatures, a rather unusual feature for U impurities in metallic hosts. For Ca $_{0.992}$ U $_{0.008}$ B $_{6}$ , the resistance minimum occurs at $T$ = 17 K. The subsequent characteristic logarithmic increase of the resistivity with decreasing temperature merges into the expected $T^{2}$ dependence below 0.8 K. Data of the low-temperature specific heat and the magnetization are analyzed by employing a simple resonance-level model. Analogous measurements on LaB $_{6}$ with a small amount of U revealed no traces of Kondo behavior, above 0.4 K.

4 pages, 4 figures, submitted for publication to Europhysics Letters

Kondo Behavior of U in CaB6​

Abstract

Kondo Behavior of U in CaB $_{6}$