Magnetic susceptibility of η-carbide-type molybdenum and tungsten carbides and nitrides

We synthesized a series of molybdenum and tungsten η-carbide-type compounds and measured their magnetic susceptibility χ. Although the enhancement of χ was observed in several compounds, apparent magnetic order was found only in Fe3W3N (ferromagnetic at 110 K). The broad peak in χ of Fe6W6C is possibly due to antiferromagnetic order. Itinerant electron metamagnetic transitions were observed in Fe3W3C, Fe6W6C, Fe6W6N and Co6W6C. The magnetic enhancement depends on the 3d element in the order Fe > Co > Ni corresponding to DOS at theFermi energy in η-12 systems, whereas no clear trend has been observed in η-6 systems.