Memory and superposition in a spin glass

TL;DR

This paper investigates non-equilibrium dynamics in a spin glass through remanent magnetisation measurements, revealing aging, memory effects, and superposition principles, and discusses the method's broader applicability.

Contribution

It demonstrates that simple dc magnetisation measurements can effectively reveal complex non-equilibrium phenomena in spin glasses.

Findings

Observation of aging and memory effects in spin glass dynamics

Validation of superposition principle in relaxation processes

Discussion of the method's applicability to other disordered magnetic systems

Abstract

Non-equilibrium dynamics in a Ag(Mn) spin glass are investigated by measurements of the temperature dependence of the remanent magnetisation. Using specific cooling protocols before recording the thermo- or isothermal remanent magnetisations on re-heating, it is found that the measured curves effectively disclose non-equilibrium spin glass characteristics such as ageing and memory phenomena as well as an extended validity of the superposition principle for the relaxation. The usefulness of this "simple" dc-method is discussed, as well as its applicability to other disordered magnetic systems.