Ordinary and Intrinsic Anomalous {{Hall}} Effects in {{Nb}}${}_{1\ensuremath{-}y}${{Fe}}${}_{2+y}$

The Hall effect of the dilution series Nb1-yFe2+y has been studied on selected samples spanning ferromagnetic (FM) and spin-density-wave (SDW) ground states, including a sample in the vicinity of the quantum critical point. Ordinary and anomalous contributions are observed, with positive ordinary Hall effect for all single crystals dominating at high temperatures. Consistent analysis of the anomalous contribution is possible for iron-rich Nb0.985Fe2.015 with ferromagnetic ground state and a SDW state at elevated temperatures and stoichiometric NbFe2 with a SDW ground state. The anomalous Hall coefficient is consistent with an intrinsic (Berry-phase) contribution, which is constant below the ordering temperature TN and gradually vanishes above TN. The ordinary Hall coefficient is positive at all temperatures with a moderate temperature dependence. For stoichiometric NbFe2 and niobium-rich Nb1.01Fe1.99\textemdash{}both having a SDW ground state\textemdash{}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.     «

The Hall effect of the dilution series Nb1-yFe2+y has been studied on selected samples spanning ferromagnetic (FM) and spin-density-wave (SDW) ground states, including a sample in the vicinity of the quantum critical point. Ordinary and anomalous contributions are observed, with positive ordinary Hall effect for all single crystals dominating at high temperatures. Consistent analysis of the anomalous contribution is possible for iron-rich Nb0.985Fe2.015 with ferromagnetic ground state and a SDW...     »