著者
Teruya Atsushi Suzuki Fuminori Aoki Dai Honda Fuminori Nakamura Ai Nakashima Miho Amako Yasushi Harima Hisatomo Hedo Masato Nakama Takao Onuki Yoshichika
出版者
The Physical Society of Japan
雑誌
Journal of the Physical Society of Japan (ISSN:00319015)
巻号頁・発行日
vol.85, no.6, pp.64716-1-10, 2016-06-01
被引用文献数
11

We succeeded in growing high-quality single crystals of the pyrite-type cubic compounds CoSe<sub>2</sub>and CoS<sub>2</sub>using the transport agent CoBr<sub>2</sub>and measured the electrical resistivity, specific heat, magnetic susceptibility, magnetization, and de Haas–van Alphen (dHvA) effect. We confirmed that CoSe<sub>2</sub>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/(K<sup>2</sup>·mol). On the other hand, CoS<sub>2</sub>is a ferromagnet with a Curie temperature <italic>T</italic><sub>C</sub>= 122 K and an ordered moment μ<sub>s</sub>= 0.93 μ<sub>B</sub>/Co. The γ of 21 mJ/(K<sup>2</sup>·mol) of CoS<sub>2</sub>is slightly larger than that of CoSe<sub>2</sub>. A large ordered moment, together with a large γ, is characteristic of CoS<sub>2</sub>because CoS<sub>2</sub>is a half-metallic spin state in the ferromagnetic state. Correspondingly, we detected a main dHvA branch with a large cyclotron effective mass of 13<italic>m</italic><sub>0</sub>in the dHvA experiments. The detected dHvA branches in CoS<sub>2</sub>and CoSe<sub>2</sub>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.
著者
Teruya Atsushi Suzuki Fuminori Aoki Dai Honda Fuminori Nakamura Ai Nakashima Miho Amako Yasushi Harima Hisatomo Hedo Masato Nakama Takao Onuki Yoshichika
出版者
The Physical Society of Japan
雑誌
Journal of the Physical Society of Japan (ISSN:00319015)
巻号頁・発行日
vol.85, no.6, pp.64716-1-10, 2016-06-01
被引用文献数
11

We succeeded in growing high-quality single crystals of the pyrite-type cubic compounds CoSe<sub>2</sub>and CoS<sub>2</sub>using the transport agent CoBr<sub>2</sub>and measured the electrical resistivity, specific heat, magnetic susceptibility, magnetization, and de Haas–van Alphen (dHvA) effect. We confirmed that CoSe<sub>2</sub>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/(K<sup>2</sup>·mol). On the other hand, CoS<sub>2</sub>is a ferromagnet with a Curie temperature <italic>T</italic><sub>C</sub>= 122 K and an ordered moment μ<sub>s</sub>= 0.93 μ<sub>B</sub>/Co. The γ of 21 mJ/(K<sup>2</sup>·mol) of CoS<sub>2</sub>is slightly larger than that of CoSe<sub>2</sub>. A large ordered moment, together with a large γ, is characteristic of CoS<sub>2</sub>because CoS<sub>2</sub>is a half-metallic spin state in the ferromagnetic state. Correspondingly, we detected a main dHvA branch with a large cyclotron effective mass of 13<italic>m</italic><sub>0</sub>in the dHvA experiments. The detected dHvA branches in CoS<sub>2</sub>and CoSe<sub>2</sub>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.