2004/03/15 by R. K. Zheng, X. X. Zhang
Physics and Astronomy · #cond-mat.other
paper · pdf · doi:10.1103/physrevlett.93.139702
published as Phys. Rev. Lett. 93, 139702 (2004) · A comment on "Phys. Rev. Lett. 91, 167206"
arxiv created 2004/03/15 · arxiv updated 2009/12/01
Recently, Sun et al reported that striking memory effects had been clearly observed in their new experiments on an interacting nanoparticle system [1]. 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 [2]. However, in our opinion, the experiments in Ref. [1] cannot evidence the existence of spin-glass-like phase at all. We will demonstrate below that all the phenomena in Ref. [1] can be observed in a non-interacting particle system with a size distribution. Numerical simulations of our experiments also display the same features.