非表示:
キーワード:
-
要旨:
Heavy-fermion systems, with their competition between Kondo and RKKY
interactions, offer a rich variety of materials that may be driven to a
magnetic quantum phase transition. Quite often, a quantum critical point
can be approached by chemical substitution, notably of isoelectric
ligands of Ce, as in CeCu6-x Au (x) and CePd1-x Ni (x) Al. While in the
former we compare pressure and concentration tuning of the magnetic
structure, the latter has the additional feature of geometric
frustration due to the distorted kagom, sublattice of Ce atoms in the
basal plane. We further present the system CeAu2Ge2 where minor
structural differences between crystals grown from Sn or Au-Ge flux lead
to pronounced differences in the magnetic structure, with several
field-induced phases in samples grown from Au-Ge flux. Finally,
non-isoelectronic substitution of Ti by V is studied in CeTi1-x V (x)
Ge-3 where CeTiGe3 is a ferromagnet, thus allowing the study of
ferromagnetic quantum criticality, a rare case for heavy-fermion
systems.
