TY - JOUR
T1 - Possible antiferroquadrupolar order in the Kondo semiconductor CeOs4Sb12
AU - Tayama, Takashi
AU - Kani, Yusuke
AU - Imai, Momota
AU - Kanai, Yuta
AU - Sugawara, Hitoshi
N1 - Publisher Copyright:
© 2021 American Physical Society.
PY - 2021/11/15
Y1 - 2021/11/15
N2 - We report the results of dc magnetization, thermal expansion, and magnetostriction measurements of the Kondo semiconductor CeOs4Sb12. These results provide a magnetic-field-temperature phase diagram for the three principal axes of the cubic crystal [100], [110], and [111] and reveal the magnetic anisotropy of the three ordered phases A, B, and C. The magnetic anisotropy of the transition temperature TC from the paramagnetic phase to the C phase is TC[111]>TC[110]>TC[100]. At low temperatures, the magnetization has a distinct magnetic anisotropy in high magnetic fields: M[100]>M[110]>M[111]. This ratio of magnetization is in good agreement with that of the magnetically anisotropic Γ67 quartet. The observation indicates that the crystalline electric field ground state is a Γ67 quartet and that the c-f hybridization effect is nearly isotropic. In addition, comparison of the present experimental results with numerical calculations of a two-sublattice model using the mean-field approximation suggests that the C phase is a Γ5-type antiferroquadrupolar ordered state despite the presence of strong c-f hybridization effects. In this case, the increase in TC due to the external field is mainly caused by the Γ2-type antiferro-octupolar interaction.
AB - We report the results of dc magnetization, thermal expansion, and magnetostriction measurements of the Kondo semiconductor CeOs4Sb12. These results provide a magnetic-field-temperature phase diagram for the three principal axes of the cubic crystal [100], [110], and [111] and reveal the magnetic anisotropy of the three ordered phases A, B, and C. The magnetic anisotropy of the transition temperature TC from the paramagnetic phase to the C phase is TC[111]>TC[110]>TC[100]. At low temperatures, the magnetization has a distinct magnetic anisotropy in high magnetic fields: M[100]>M[110]>M[111]. This ratio of magnetization is in good agreement with that of the magnetically anisotropic Γ67 quartet. The observation indicates that the crystalline electric field ground state is a Γ67 quartet and that the c-f hybridization effect is nearly isotropic. In addition, comparison of the present experimental results with numerical calculations of a two-sublattice model using the mean-field approximation suggests that the C phase is a Γ5-type antiferroquadrupolar ordered state despite the presence of strong c-f hybridization effects. In this case, the increase in TC due to the external field is mainly caused by the Γ2-type antiferro-octupolar interaction.
UR - http://www.scopus.com/inward/record.url?scp=85120696696&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.104.195144
DO - 10.1103/PhysRevB.104.195144
M3 - 学術論文
AN - SCOPUS:85120696696
SN - 2469-9950
VL - 104
JO - Physical Review B
JF - Physical Review B
IS - 19
M1 - 195144
ER -