Study on competition between the Kondo effect and intersite multipole interactions in cerium-lanthanum hexaborides

我们测量了六硼化铈镧的比热和弹性常数。我们证实了Ce0.5La0.5B6在低温低场条件下可以实现非磁性态。这种非磁性态被磁场破坏，并诱导出有序态。非磁性态的低温比热与T^（1.5）成正比。这表明非磁性态不同于重费米子态。我们还在Ce0.75La0.25B6体系中发现了一个新的磁相（phase IV）。第四期的序参量尚未确定。我们发现Ce0.75La0.25B6在第四相的比热与T^2成正比。这种比热的行为特征与反铁磁状态是矛盾的。

We have measured specific heat and elastic constants of cerium-lanthanum hexaborides. We have confirmed that a non-magnetic state is realized in Ce0.5La0.5B6 at low-temperatures and low fields. This non-magnetic state is destroyed by the fields, and an ordered state is induced. Low-temperature specific heat of the non-magnetic state is in proportion to T^(1.5). This indicates that the non-magnetic state is distinct from heavy Fermion state. We have also found that a new magnetic phase (Phase IV) in the Ce0.75La0.25B6 system. The order parameter of phase IV has not been identified yet. We have found that the specific heat of Ce0.75La0.25B6 in phase IV is in proportion to T^2. This behavioral feature of the specific heat is contradictory to an antiferro-magnetic state.