Quantum critical behavior in a CePt ferromagnetic Kondo lattice

6 p. : il.Most of the studies of heavy fermions near a quantum critical point QCP have been carried out on antiferromagnetic systems. In this paper we report on the disappearance of ferromagnetic FM order in CePt as seen by the ac magnetic susceptibility and the electrical resistance measurements under pressures P up to 15 GPa. The pressure dependence of the Curie temperature TC P follows a typical Doniach’s phase diagram for Kondo lattice systems and it is consistent with a QCP at the critical pressure PC 12.1 GPa. The resistance in the vicinity of the QCP shows clearly a non-Fermi liquid NFL and beyond that a Fermi liquid FL state is recovered. A semiquantitative discussion on the nature of the vanishing of TC in a FM Ce Kondo lattice is given for the first time

Phase diagram of the heavy fermion system YbFe/sub 2/Ge/sub 2/ under pressure

The phase diagram of the heavy fermion compound YbFe2Ge2 under high pressures P ≤ 18.2 GPa was obtained by electrical resistivity measurements. Pressure drives the system from a paramagnetic Fermi liquid state to a magnetically ordered state, with a quantum critical point at PC ≈ 9.4 GPa. In the vicinity of PC a non-Fermi-liquid behavior ascribed to two-dimensional antiferromagnetic fluctuations is observed. In the magnetic side, the resistivity shows the existence of spin-wave excitations characteristic of an antiferromagnet

Phase diagram of the heavy fermion system YbFe/sub 2/Ge/sub 2/ under pressure

The phase diagram of the heavy fermion compound YbFe2Ge2 under high pressures P ≤ 18.2 GPa was obtained by electrical resistivity measurements. Pressure drives the system from a paramagnetic Fermi liquid state to a magnetically ordered state, with a quantum critical point at PC ≈ 9.4 GPa. In the vicinity of PC a non-Fermi-liquid behavior ascribed to two-dimensional antiferromagnetic fluctuations is observed. In the magnetic side, the resistivity shows the existence of spin-wave excitations characteristic of an antiferromagnet