Aging phenomena in spin-glass and ferromagnetic phases: Domain growth and wall dynamics
Service de Physique de l'Etat Condensé, CEA Saclay
91191 Gif-sur-Yvette Cedex, France
Accepted: 24 March 2000
We compare aging in a disordered ferromagnet and in a spin-glass, by studying the different phases of a re-entrant system. We have measured the relaxation of the low-frequency ac susceptibility χ, in both the ferromagnetic and spin-glass phases of a 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.
PACS: 75.50.Lk – Spin-glasses and other random magnets / 75.10.Nr – Spin-glass and other random models / 75.40.Gb – Dynamic properties (dynamic susceptibility, spin waves, spin diffusion, dynamic scaling, etc.)
© EDP Sciences, 2000