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

E. Vincent; V. Dupuis; M. Alba; J. Hammann; J.-P. Bouchaud

doi:doi:10.1209/epl/i2000-00323-8

DOI: 10.1209/epl/i2000-00323-8

Europhys. Lett., 50 (5), p. 674 (2000)

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

E. Vincent - V. Dupuis - M. Alba - J. Hammann - J.-P. Bouchaud

Service de Physique de l'Etat Condensé, CEA Saclay
91191 Gif-sur-Yvette Cedex, France

(Received 9 August 1999; accepted in final form 24 March 2000)

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.)

Abstract:

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 $\chi$ , in both the ferromagnetic and spin-glass phases of a $\rm CdCr_{1.9}In_{0.1}S_4$ 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.

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