Indexed on: 15 Mar '04Published on: 15 Mar '04Published in: Physics - Other
Recently, Sun et al reported that striking memory effects had been clearly observed in their new experiments on an interacting nanoparticle system . They claimed that the phenomena evidenced the existence of a spin-glass-like phase and supported the hierarchical model. No doubt that a particle system may display spin-glass-like behaviors . However, in our opinion, the experiments in Ref.  cannot evidence the existence of spin-glass-like phase at all. We will demonstrate below that all the phenomena in Ref.  can be observed in a non-interacting particle system with a size distribution. Numerical simulations of our experiments also display the same features.