Aging phenomena in spin glass and ferromagnetic phases: domain growth and wall dynamics

TL;DR

This study compares aging phenomena in disordered ferromagnets and spin glasses, revealing how domain growth and wall dynamics influence aging, memory, and rejuvenation effects across different phases.

Contribution

It provides new insights into the mechanisms of aging in spin glasses and ferromagnets, highlighting the roles of domain growth and wall reconformations.

Findings

Aging processes restart with temperature drops in both phases.

Memory effects can be erased by domain growth in ferromagnets.

Wall reconformations dominate aging in spin glasses.

Abstract

We compare aging in a disordered ferromagnet and in a spin glass, by studying the different phases of a reentrant system. We have measured the relaxation of the low-frequency ac susceptibility, in both the ferromagnetic and spin-glass phases of a CdCr_{1.9}In_{0.1}S_4 sample. A restart of aging processes when the temperature is lowered (`chaos-like' effect) is observed in both phases. The memory of previous aging at a higher temperature can be retrieved upon re-heating, but in the ferromagnetic phase it can rapidly be erased by the growth of ferromagnetic domains. We interpret the behaviour observed in the ferromagnetic phase in terms of a combination of domain growth and pinned wall reconformations, and suggest that aging in spin glasses is dominated by such wall reconformation processes.