Geometric Frustration in Itinerant Electron Magnets

We review two possible geometrically frustrated lattices among itinerant electron magnets. One is a dimer‐bridged octahedral lattice found in Mo3Sb7, where frustration‐induced lattice instability has been observed. Another is the stella quadrangula lattice found in η‐carbide‐type compounds. The quantum critical behavior observed in Fe3Mo3N is discussed in connection with the unique frustration expected in the stella quadrangula lattice.