Abstract
We report the synthesis of single crystals of a binary heavy-fermion system . An unusual double phase transition is observed in specific heat measurements at and , signaling a magnetically ordered ground state. The complete magnetic field-temperature phase diagram of is obtained from the magnetic field dependence of the electrical resistivity and specific heat , and consists of two phase lines terminating at finite temperature critical endpoints. Electrical resistivity and specific heat measurements show that the magnetically ordered state is a Fermi liquid with strong electronic correlations, absent in the paramagnetic state. At higher temperatures, strong magnetic anisotropy is observed, which we ascribe to crystal electric field effects acting on a well localized moment, yielding a well separated doublet ground state, confirmed by inelastic neutron scattering measurements. Our measurements show that is a heavy-fermion compound which is very near a quantum critical point.
2 More- Received 29 June 2006
DOI:https://doi.org/10.1103/PhysRevB.74.224431
©2006 American Physical Society