Nonlinear Susceptibility and Magnetic Ordering of MCl2-GICs
Graphite intercalation compounds (GIC) are complex systems in which each intercalant layer is separated by a certain number (stage num.) of carbon layers. Besides such a staged structure, GICs have a characteristic island structure, in which each intercalant layer is divided into “mesoscopic” clusters (islands) . Among these, NiCl2- and CoCl2-GICs have been studied as interesting model systems of a two-dimensional (2D) XY-type ferromagnet . An observed two-step magnetic phase transition at Tcu and Tc1 (<Tcu) with a purely 2D long-range order in the intermediate temperature range can be understood by a combined effect of good 2D nature and mesoscopic cluster size as a successive ordering such as disorder ⇌ interisland (2D) order ⇌ interisland (3D) order [2,3]. The detail of the ordered structure below Tcu, however, is not yet clear although a neutron scattering experiment  and a series of magnetic measurements [2,3] have shown very interesting phenomena suggesting a XY type of intraisland interaction and a glasslike nature of complicated interisland interaction.
KeywordsHarmonic Component Nonlinear Susceptibility Graphite Intercalation Compound Intermediate Temperature Range Intercalant Layer
- 2.M. Matsuura: Ann. Phys. Suppl. (Paris) 11, 117 (1986)Google Scholar