Hall resistivity PH has been studied for single crystals of Nd2Mo2O7, which
has the ferromagnetic and chiral ordered state. Effects of Ti-doping on PH
have also been studied down to 3 K under the magnetic field (H) up to 7 T.
The T- and H-regions of the measurements have boon extended for non-doped
samples to 50 mK and 15 T, respectively. From the results, it has been conf
irmed that two components of the anomalous Hall resistivity exist. One. is
proportional to tho net magnetization of Mo atoms, M-Mo. It changes its sig
n with the doping. The other is proportional to the net magnetization of Nd
atoms, M-Nd and does not exhibit the sign change. The Hall resistivity has
a finite and almost T-independent value at very low temperatures. The,,,(,
results on the behavior of rho (H) are discussed by considering the existi
ng theories including the one recently proposed by a mechanism related to t
he spin chiral order.