Unusual Field-Insensitive Phase Transition and Kondo Behavior in SmTi2Al20

作者：Higashinaka Ryuji^*; Maruyama Takuya; Nakama Akihiro; Miyazaki Ryoichi; Aoki Yuji; Sato Hideyuki

来源：Journal of the Physical Society of Japan, 2011, 80(9): 093703.

DOI：10.1143/JPSJ.80.093703

• caged structure
• heavy fermion
• magnetization
• transport
• specific heat

Magnetization, electrical resistivity and specific heat measurements were performed on high-quality single crystalline SmTi2Al20 (residual resistivity ratio similar to 40) grown by Al self-flux method. A Kondo-like log T dependence in the resistivity is observed below 50 K. We discovered a field-insensitive phase transition at T-x = 6.5K and a field-insensitive heavy fermion behavior with the electronic specific heat coefficient gamma = 150 mJ/(K-2 mol). Specific heat analysis reveals that the ground state is a Gamma(8) quartet state and the Sm magnetic dipole moment m(Sm) (similar to 0.5 mu(B) at T similar or equal to 0) orders below T-x in spite of the field-insensitive behavior. Possible reasons for the field insensitiveness will be discussed.

• 出版日期2011-9