Ce 3 Pt 23 Si 11 ferromagnet: unusual magnetic behavior brought to light by neutron studies

The ternary system R-Pt-Si (R = rare earth element) triggers a lot of interest, due to peculiar physical behaviors of some compounds: unconventional superconductivity, heavy-fermion properties, coexistence of superconductivity and magnetic ordering..., such as CePt3Si, reported as the first non-centro symmetric heavy fermion superconductor. Actually, several studies let suppose a sample dependence of the superconductivity and for instance, in Ce deficient samples, the coexistence of a new phase, Ce3Pt23Si11, was suspected to interfere with superconducting properties. We have undertaken an extended investigation on this new phase.