Magnetic and transport properties of the pyrochlore molybdate R2-cursive Greek chiR′cursive Greek chi-Mo2O7 (R, R′ = rare earth, Y), which exhibits the metal-insulator (M-I) transition with varying cursive Greek chi, have been studied. The transition from an antiferromagnetic spin-glass state to a ferromagnetic one occurs at cursive Greek chi far from the M-I phase boundary, indicating that the intimate correlation of the magnetic state with the conducting nature is not so obvious. In Nd2Mo2O7, the ordering of Mo spins takes place at about 95 K, where the anomalous Hall resistivity appears with decreasing temperature T along with the spontaneous magnetization. With the ordering of Nd moments which becomes significant below ∼20 K with decreasing T, the behavior of the anomalous Hall resistivity markedly changes, while the Mo-magnetization is partially cancelled by the Nd magnetization. It is shown that the anomalous Hall resistivity can be described by two components, 4πRsMMo, and 4πR′sMNd, the contributions from the uniform magnetizations MMo and MNd of Mo and Nd moments, respectively. The sign of R′s is opposite to that of Rs. Brief arguments are given if the unusual behavior of the Hall resistivity is related with the nonzero chirality of the magnetic moment system.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)