Magnetism of new semi-Heusler compounds FeVSn and CoVSn

Magnetic properties of new intermetallics FeVSn and CoVSn are reported. Both materials belong to the group of semi-Heusler compounds, with lattice parameters of 0.593 and 0.598 nm respectively in a cubic MgAgAs structure. X-ray investigations indicate partial atomic ordering in both cases. Ferromagnetic order was observed in FeVSn with T/sub c/=86 K. The saturation moment obtained by M versus H measurements at 4 K has a value of 0.45 Gig, indicating that FeVSn is a weak itinerant ferromagnet. CoVSn was found to be paramagnetic with no magnetic ordering down to 2 K. Room-temperature /sup 51/V NMR spectra were used as a local probe of the magnetic behavior of these materials. The results Indicate that V d orbitals play a strong role in the magnetism of FeVSn. Results for CoVSn are consistent with predicted semiconducting or semimetallic behavior for this material.