The random-field Ising model (RFIM) system Fe0.42Zn0.58F2 is studied by mag
netization and AC susceptibility measurements, under finite DC applied fiel
ds (H). For weak random fields (corresponding to H < 20 KOe), the phase tra
nsition (PT) at T-c (H) is accompanied by the critical slowing down inheren
t to the random field problem. For higher H, the PT is destroyed and a glas
sy dynamics dominates the magnetic behavior. (C) 2001 Elsevier Science BY.
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