TY - JOUR
T1 - Large cyclotron mass and large ordered moment in ferromagnet CoS2 compared with paramagnet CoSe2
AU - Teruya, Atsushi
AU - Suzuki, Fuminori
AU - Aoki, Dai
AU - Honda, Fuminori
AU - Nakamura, Ai
AU - Nakashima, Miho
AU - Amako, Yasushi
AU - Harima, Hisatomo
AU - Hedo, Masato
AU - Nakama, Takao
AU - Onuki, Yoshichika
N1 - Funding Information:
We are very grateful to Professor K. Ueda for helpful discussions. This work was supported by JSPS KAKENHI Grant Numbers 15H05884, 25247055, and 15H05886.
Publisher Copyright:
©2016 The Physical Society of Japan.
PY - 2016/6/15
Y1 - 2016/6/15
N2 - We succeeded in growing high-quality single crystals of the pyrite-type cubic compounds CoSe2 and CoS2 using the transport agent CoBr2 and measured the electrical resistivity, specific heat, magnetic susceptibility, magnetization, and de Haas-van Alphen (dHvA) effect. We confirmed that CoSe2 is an exchange-enhanced paramagnet revealing a broad maximum at around 50 K in the temperature dependence of the magnetic susceptibility. The electronic specific heat coefficient is moderately large, γ = 18 mJ=(K2·mol). On the other hand, CoS2 is a ferromagnet with a Curie temperature TC = 122 K and an ordered moment μs = 0.93 μB/Co. The γ of 21 mJ=(K2·mol) of CoS2 is slightly larger than that of CoSe2. A large ordered moment, together with a large γ, is characteristic of CoS2 because CoS2 is a half-metallic spin state in the ferromagnetic state. Correspondingly, we detected a main dHvA branch with a large cyclotron effective mass of 13m0 in the dHvA experiments. The detected dHvA branches in CoS2 and CoSe2 are discussed on the basis of the results of energy band calculations, revealing a broken fourfold symmetry in the angular dependence of the dHvA frequency.
AB - We succeeded in growing high-quality single crystals of the pyrite-type cubic compounds CoSe2 and CoS2 using the transport agent CoBr2 and measured the electrical resistivity, specific heat, magnetic susceptibility, magnetization, and de Haas-van Alphen (dHvA) effect. We confirmed that CoSe2 is an exchange-enhanced paramagnet revealing a broad maximum at around 50 K in the temperature dependence of the magnetic susceptibility. The electronic specific heat coefficient is moderately large, γ = 18 mJ=(K2·mol). On the other hand, CoS2 is a ferromagnet with a Curie temperature TC = 122 K and an ordered moment μs = 0.93 μB/Co. The γ of 21 mJ=(K2·mol) of CoS2 is slightly larger than that of CoSe2. A large ordered moment, together with a large γ, is characteristic of CoS2 because CoS2 is a half-metallic spin state in the ferromagnetic state. Correspondingly, we detected a main dHvA branch with a large cyclotron effective mass of 13m0 in the dHvA experiments. The detected dHvA branches in CoS2 and CoSe2 are discussed on the basis of the results of energy band calculations, revealing a broken fourfold symmetry in the angular dependence of the dHvA frequency.
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U2 - 10.7566/JPSJ.85.064716
DO - 10.7566/JPSJ.85.064716
M3 - Article
AN - SCOPUS:84973902097
SN - 0031-9015
VL - 85
JO - Journal of the Physical Society of Japan
JF - Journal of the Physical Society of Japan
IS - 6
M1 - 064716
ER -