TY - JOUR
T1 - Strong field quenching of the quasiparticle effective mass in heavy fermion compound YbCo2Zn20
AU - Ohya, Masahiro
AU - Matsushita, Masaki
AU - Yoshiuchi, Shingo
AU - Takeuchi, Tetsuya
AU - Honda, Fuminori
AU - Settai, Rikio
AU - Tanaka, Toshiki
AU - Kubo, Yasunori
AU - Onuki, Yoshichika
PY - 2010/8
Y1 - 2010/8
N2 - 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.
AB - 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.
KW - Cyclotron effective mass
KW - Fermi surface
KW - Heavy fermion
KW - Metamagnetism
KW - YbCoZn
KW - dHvA
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U2 - 10.1143/JPSJ.79.083601
DO - 10.1143/JPSJ.79.083601
M3 - Article
AN - SCOPUS:77956441247
VL - 79
JO - Journal of the Physical Society of Japan
JF - Journal of the Physical Society of Japan
SN - 0031-9015
IS - 8
M1 - 083601
ER -