Geometric frustration in the stella quadrangula lattice and metamagnetism in Fe3Mo3N

η-carbide-type transition-metal compounds, which include the stella quadrangula lattice, are good candidates for testing the geometric frustration in the itinerant electron magnet. The broad peak observed in the temperature dependence of the susceptibility for one of the η-carbide-type bimetallic nitrides, Fe3Mo3N, has been confirmed microscopically by 95Mo NMR Knight-shift measurements. The itinerant electron metamagnetic transition observed in this compound is discussed in connection with the χ(T) behavior.