摘要
The low-temperature properties of single crystals of SmTa2Al20 have been studied by electrical resistivity, magnetization, and specific heat measurements. A lambda-type peak structure, indicating a phase transition, was found in the specific heat at T-x = 2.0 K. From an analysis of the nuclear specific heat contribution, the ordered moment is estimated to be 0.22 mu(B)/Sm, which is largely suppressed from 0.84 mu(B)/Sm for a free Sm3+ ion. The Kondo-like -log T dependence of resistivity and the suppressed effective magnetic moment of 0.09 mu(B)/Sm above T-x indicate strong c-f hybridization. The largely enhanced specific heat divided by temperature of about 3J/(mol K-2) below 0.4 K suggests the formation of extremely heavy quasiparticles in the ordered state. A notable feature commonly observed in all of these behaviors is robustness against magnetic fields. We discuss the possible relevance of multipole moments in the quartet ground state to the robustness against magnetic fields.
- 出版日期2013-12