Geometric frustration in the RMn2 Laves phase compounds

An overview of neutron-scattering investigations of the geometrically frustrated Mn itinerant-electron magnetism in the RMn2 Laves phase compounds is given. Magnetic structures of magnetically ordered compounds are briefly described, in particular the mixed phases where magnetic and nonmagnetic Mn coexist. Magnetic correlations in the paramagnetic phase of YMn2 and in (Y0.97Sc0.03)Mn2, where the substitution of Sc for Y inhibits the magnetic order down to the lowest temperatures, are then discussed. An unusual neutron-scattering function S(Q, (omega)) is measured, which appear to arise from an itinerant-electron spin liquid.