Spin-glass-like transition and Hall resistivity of Y2-xBixIr2O7

Various physical properties of the pyrochlore oxide Y2-xBixIr2O7 have been studied. The magnetizations M measured under the conditions of the zero-field-cooling (ZFC) and the field-cooling (FC) have different values below the temperature T = T-G. The anomalous T-dependence of the electrical resistivities rho and the thermoelectric powers S observed at around T-G indicates that the behavior of the magnetization is due to the transition to the state with the spin freezing. In this spin-frozen state, the Hall resistivities rho(H) measured with the ZFC and FC conditions are found to have different values, too, in the low temperature phase (T < T-G). Possible mechanisms which induce such the hysteretic behavior are discussed.