Strong field quenching of the quasiparticle effective mass in heavy fermion compound YbCo2Zn20

Masahiro Ohya, Masaki Matsushita, Shingo Yoshiuchi, Tetsuya Takeuchi, Fuminori Honda, Rikio Settai, Toshiki Tanaka, Yasunori Kubo, Yoshichika Onuki

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33 Citations (Scopus)

Abstract

We found a metamagnetic like anomaly at Hm ≃ 5 kOe in a heavy fermion compound YbCo2Zn20 below the characteristic temperature TXmax = 0:32 K where the ac-susceptibility shows a broad peak, suggesting that an electronic state with a very low Kondo temperature is realized. Interestingly, the metamagnetic like behavior was observed as two peaks at 4.0 and 7.5 kOe at 95 mK in the magnetic field dependence of the electronic specific heat C/T. The extremely large values of the electronic specific heat coefficient γ ≃ 8000mJ/(K2·mol) and A = 160μΩ·cm/K2 in the electrical resistivity p = p0 + AT2 at H = 0kOe are most likely due to the very low Kondo temperature. The √A value was, however, found to be strongly reduced from √A = 12:6 (μΩ·cm/K2)1/2 at 0kOe to 0.145(μΩ·cm/K2)1/2 at 150kOe. Therefore, we considered that the corresponding cyclotron effective mass m c*, which was determined from the temperature dependence of the de Haas-van Alphen (dHvA) amplitude, is also reduced with increasing magnetic field and is in fact not large, ranging from 2 to 9m 0 at 117kOe. From the field dependence of √A and m c*, we estimated the cyclotron effective mass at 0kOe to be 100{500m0, revealing the largest cyclotron mass as far as we know.

Original languageEnglish
Article number083601
Journaljournal of the physical society of japan
Volume79
Issue number8
DOIs
Publication statusPublished - 2010 Aug
Externally publishedYes

Keywords

  • Cyclotron effective mass
  • Fermi surface
  • Heavy fermion
  • Metamagnetism
  • YbCoZn
  • dHvA

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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