Resistance anomalies accompanying crossover from heavy-fermion regime to intermediate-valence regime: A study of Cu-Ni substitution and pressure effects on CeCu2Si2

Yoichi Ikeda, Yuzo Ito, Shingo Araki, Tatsuo Kobayashi, Hideki Yoshizawa

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We present detailed investigations on the effects of Ni substitution (x) on Ce(Cu1-xNix)2Si2 with x <0.3, and a pressure (p) study for x = 0.04(2), 0.05(2), and 0.09(2) by resistivity measurements. The Cu-Ni substitution suppresses both antiferromagnetic fluctuations and superconductivity in CeCu2Si2, and leads to a dramatic crossover from the heavy-fermion (HF) regime to the intermediate-valence (IV) regime with progressive Ni doping. The crossover can be characterized by a marked increase in Kondo temperature evaluated from resistivity, specific heat, and susceptibility measurements. In high-pressure resistivity measurements, the Ni-doped system exhibits similar anomalies to those observed in CeCu2Si2, namely, T-linear dependence, an enhancement of residual resistivity, and a marked decrease in the A coefficient of the T2-resistivity. Furthermore, we observed an unexpected upturn anomaly in resistivity in the Ni-doped system under high pressure. By constructing the x-p phase diagram of Ce(Cu1-xNix)2Si2, we demonstrate that the crossover from the HF regime to the IV regime can be associated with these characteristic anomalies in resistivity.

Original languageEnglish
Article number024702
JournalJournal of the Physical Society of Japan
Issue number2
Publication statusPublished - Feb 15 2015


ASJC Scopus subject areas

  • Physics and Astronomy(all)

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