27Al-NQR/NMR Study of Kondo Semiconductor CeFe2Al10

概要

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27Al-NQR/NMR measurements have been performed on CeFe2Al10 in relevance to the novel phase below $T_{0}=27$ K of isostructural CeRu2Al10. NQR peaks are assigned to five crystallographically inequivalent Al sites. No splitting of the NQR spectra down to 1.5 K confirms the lack of phase transition in this compound. The gaplike decrease in the spin–lattice relaxation rate $1/T_{1}$ above about 20 K, following the Korringa law ($T_{1}T = \text{const.}$) below 20 K, indicates a pseudogap opening near the Fermi level. The gap magnitude of 70 K with a mid-gap state of 42% is estimated based on a rectangular density of states. The gap magnitude is much larger than the gap of 15 K evaluated previously from the electrical resistivity, which suggests CeFe2Al10 to be a Kondo semiconductor with a Kondo temperature much higher than 300 K.
2010-10-15