  Ni3V2O8 and Co3V2O8 have spin-1 and spin-3/2 magnetic lattices that are a new
anisotropic variant of the Kagome net, wherein edge-sharing MO6 octahedra form
the rises and rungs of a "Kagome staircase". The anisotropy largely relieves
the geometric frustration, but results in rich magnetic behavior.
Characterization of the magnetization of polycrystalline samples reveals that
the compounds are ferrimagnetic in character. Heat capacity measurements show
the presence of four magnetic phase transitions below 9 K for Ni3V2O8 and two
below 11 K for Co3V2O8. Comparison to the low temperature heat capacity of
isostructural nonmagnetic Zn3V2O8 provides an estimate of the magnetic entropy
involved with the phase transitions. The results suggest that Co3V2O8 may
display magnetic transitions below 2 K.
