We present evidence for unconventional superconducting fluctuations in a heavy-fermion compound CeNi 2Ge 2. The temperature dependence of the 73Ge nuclear-spin-lattice-relaxation rate 1/T 1 indicates the development of magnetic correlations and the formation of a Fermi-liquid state at temperatures lower than T FL = 0.4 K, where 1/T 1T is constant. The resistance and 1/T 1T measured on an as-grown sample decrease below T c onset = 0.2 K and T c NQR = 0.1 K, respectively; these are indicative of the onset of superconductivity. However, after annealing the sample to improve its quality, these superconducting signatures disappear. These results are consistent with the emergence of unconventional superconducting fluctuations in close proximity to a quantum critical point from the superconducting to the normal phase in CeNi 2Ge 2.
|ジャーナル||journal of the physical society of japan|
|出版ステータス||Published - 4月 2006|
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