A Comment on "Memory Effects in an Interacting Magnetic Nanoparticle System"

TL;DR

This paper critiques a recent study claiming to observe spin-glass-like memory effects in an interacting nanoparticle system, arguing that similar phenomena can occur in non-interacting systems and questioning the original interpretation.

Contribution

It provides a critical analysis showing that observed memory effects are not exclusive to interacting systems and can be reproduced without interactions, challenging previous claims.

Findings

Memory effects can be observed in non-interacting nanoparticle systems.

Numerical simulations replicate the phenomena without particle interactions.

The original experiments do not conclusively evidence a spin-glass-like phase.

Abstract

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.