Investigation of dynamical magnetic properties in spin ice pyrochlore Dy2Ti2O7

The frequency and temperature dependence of the spin relaxation processes were studied, to understand the dynamics of the spin interactions in typical spin ice compound Dy₂Ti₂O₇. Two transition peaks were found in ac susceptibilities for frequencies higher than 150 Hz at temperatures around 15 K and 2 K. However, the relaxation times and activation energies were different at corresponding transition temperatures, suggesting the existence of two types of dynamical behavior. The results for high temperature activation energy was 70 K, which was much lower than other reported data of 220 K.