  We report a density functional study of the electronic structure and
magnetism of Y2Ni7. The results show itinerant magnetism very similar to that
in the weak itinerant ferromagnet Ni3Al. The electropositive Y atoms in Y2Ni7
serves to donate charge to the Ni host mostly in the form of $s$ electrons. The
non-spin-polarized state shows a high density of states at the Fermi level,
N(EF) due to flat bands. This leads to the ferromagnetic instability. However,
there are also several much more dispersive bands crossing E(F), which should
promote the conductivity. Spin fluctuation effects appear to be comparable to
or weaker than Ni3Al, based on comparison with experimental data. Y2Ni7
provides a uniaxial analogue to cubic Ni3Al for studying weak itinerant
ferromagnetism, suggesting detailed measurements of its low temperature
physical properties and spin fluctuations, as well experiments under pressure.
