title: Magnetic field induced sign reversal of the anomalous Hall effect in a pyrochlore ferromagnet Nd2Mo2O7: evidence for a spin chirality mechanism.
abstract: The anisotropic Hall effect and magnetization have been investigated for single crystals of Nd2Mo2O7 under high magnetic fields up to 27 T and at low temperatures down to 50 mK. The magnetization curves indicate that the Nd moments with strong Ising anisotropy are coupled antiferromagnetically with the Mo spins and show field-induced flipping on the respective sites. The Hall resistivity changes its sign with increasing field applied along the [111] direction, while it monotonously approaches zero with the field applied along the [100] or [110] direction. This behavior is in accord with the prediction by the Berry phase theory and is interpreted in terms of the field-induced reversal of spin chirality on the pyrochlore lattice.
authors.affiliation: Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Taguchi
authors.forename: T
authors.initials: T
authors.lastname: Sasaki
authors.forename: S
authors.initials: S
authors.lastname: Awaji
authors.forename: Y
authors.initials: Y
authors.lastname: Iwasa
authors.forename: T
authors.initials: T
authors.lastname: Tayama
authors.forename: T
authors.initials: T
authors.lastname: Sakakibara
authors.forename: S
authors.initials: S
authors.lastname: Iguchi
authors.forename: T
authors.initials: T
authors.lastname: Ito
authors.forename: Y
authors.initials: Y
authors.lastname: Tokura