^<209>Bi-NQR Investigation of the Non-magnetic Heavy-fermion Compound CeRhBi (Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties)

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We report the results of ^<209>Bi-NQR measurements on the heavy-fermion compound CeRhBi with the large electronic specific heat coefficient γ 〜 500mJ/mol-K^2 at 2K. From the Bi-NQR spectra, it is proved that no magnetic ordering occurs down to 0.15 K. The temperature dependence of nuclear spin-lattice relaxation rate 1/T_1 clearly demonstrates a crossover from a localized regime at high temperature to an itinerant ground state with the Kondo temperature T_K of about 8 K. It is, therefore, revealed that CeRhBi is a typical heavy-fermion compound with a non-magnetic ground state, closely located at a quantum critical point. In the context of CeRhPn (Pn = Bi, Sb, As) series, where all compounds crystallize in the same orthorhombic ε-TiNiSi-type structure, no trace of gap formation is observed in 1/T_1 down to 0.2 K in CeRhBi, although the values of 1/T_1 in the Kondo semiconductors CeRhSb and CeRhAs markedly decrease at low temperatures due to the presence of excitation gap.
社団法人日本物理学会の論文
2004-03-15