Ferromagnetic and ferroelectric quantum phase transitions

The applicability of mean field models of ferroelectric and ferromagnetic quantum critical points is examined for a selection of d‐electron systems. Crucially, we find that the tendency of the effective interaction between critical fluctuation modes to become attractive and anomalous as the ordering temperatures tend to absolute zero results in particularly complex and striking phenomena. The multiplicity of quantum critical fields at the border of metallic ferromagnetism, in particular, is discussed here.