  The Hall effect on selected samples of the dilution series Nb1-yFe2+y is
studied. Normal and anomalous contributions are observed, with positive normal
Hall effect dominating at high temperatures. Consistent analysis of the
anomalous contribution is only possible for Fe-rich Nb0.985Fe2.015 featuring a
ferromagnetic ground state. Here, a positive normal Hall coefficient is found
at all temperatures with a moderate maximum at the spin-density-wave
transition. The anomalous Hall effect is consistent with an intrinsic
(Berry-phase) contribution which is constant below the ordering temperature TC
and continuously vanishes above TC. For stoichiometric NbFe2 and Nb-rich
Nb1.01Fe1.99 - both having a spin-density-wave ground state - an additional
contribution to the Hall resistivity impedes a complete analysis and indicates
the need for more sophisticated models of the anomalous Hall effect in
itinerant antiferromagnets.
