Magnetic Properties of Ruthenium Pyrochlores Y2Ru2O7and Lu2Ru2O7

Magnetic susceptibility and magnetic hysteresis measurements were performed for Y2Ru2O7and Lu2Ru2O7, which show magnetic transitions at 80 and 85 K, respectively. Below the transition temperatures, there is a large difference in the temperature dependence of the magnetization measured between under zero-field cooled condition and under field-cooled condition, but no magnetic hysteresis has been observed. These results suggest that below the temperatures, both Y2Ru2O7and Lu2Ru2O7transform to a spin-glass state which is independent of the applied magnetic field.