Enhancement of anomalous Hall effect in a filling-changed pyrochlore-type molybdate
Department of Applied Physics,
University of Tokyo - Tokyo 113-8656, Japan
2 Correlated Electron Research Center (CERC) and Joint Research Center for Atom Technology (JRCAT) - Tsukuba 305-0046, Japan
Accepted: 22 February 2001
Anomalous Hall effect has been investigated for metallic ferromagnets with a pyrochlore lattice, (SmCax)2Mo2O7, with x=0 and 0.1. While longitudinal conductivity and magnetization undergo little change upon the partial Ca substitution, the anomalous Hall effect or transverse conductivity increasing toward low temperature is drastically enhanced. Comparison with a Y-doped compound (Sm0.9Y0.1)2Mo2O7 has revealed that the change of band filling is essential for the large variation in the transverse conductivity. By measurements of AC susceptibility, a glassy nature is indicated for the ferromagnetic state of the Ca-doped compound, which arises perhaps from an increased tilting angle of Mo spins. The resultant enhancement of the spin chirality and the associated Berry phase are likely responsible for the drastic increase of the anomalous Hall effect.
PACS: 75.50.-y – Studies of specific magnetic materials / 72.20.My – Galvanomagnetic and other magnetotransport effects / 72.15.Gd – Galvanomagnetic and other magnetotransport effects
© EDP Sciences, 2001