Low temperature linear dynamical susceptibility of dipolar spin glasses

The dissipative part of the linear magnetic dynamic susceptibility of dipolar spin glasses is considered. Due to the transition of the system (at enough high concentration of the magnetic dipoles) from a paramagnetic phase to a magnetic dipolar one, an anomalous temperature dependence of the dissipative part of the magnetic susceptibility is found. Some considerations related to the experimental results for LiHoxY 1−xF4 are made.