•S. Drotziger1, C. Pfleiderer1, M. Uhlarz1,
H. v. Löhneysen1,2, D. Souptel3, W. Löser3
und G. Behr3
1Physikalisches Institut, Universität Karlsruhe, D-76128
Karlsuhe
2Forschungszentrum Karlsruhe, Institut für Festkörperphysik,
D-76021 Karlsuhe
3Institut of Solid State and Materials Research Dresden,
Postfach 270116, D-01171 Dresden
Silicon deficient CeSi2-x crystallizes over a large range
of compositions in the orthorhombic a-GdSi2
structure. Below a critical Si content, easy-plane ferromagnetism is observed.
Being one of the rare examples of a ferromagnetic Ce compound, the nature
of this ferromagnetic state has been studied intensively in the past. Here
we report a high pressure study of the magnetisation of a new generation
of CeSi2-x single crystals grown with an optical floating zone
furnace under ultrapure conditions. In CeSi1.81 where TC
= 9.5 K, moderate pressures are sufficient to suppress ferromagnetism.
The easy-plane ferromagnetic to paramagnetic quantum phase transition is
compared with the predictions of weak-coupling spin fluctuation theory.