Superspin glass aging behavior in textured and nontextured frozen ferrofluid

Sawako Nakamae (1) , Emmanuelle Dubois (2) , Vincent Dupuis (2) , Denis L'Hôte (1) , Régine Perzynski (2) , Eric Vincent (1) , Caroline Thibierge (1)

1 SPEC - UMR3680 - Service de physique de l'état condensé
2 PECSA - Physicochimie des Electrolytes, Colloïdes et Sciences Analytiques

The effect of magnetic anisotropy-axis alignment of individual nanoparticles on the collective aging behavior in the superspin glass state of a frozen ferrofluid has been investigated. The ferrofluid studied here consists of maghemite nanoparticles (γ-Fe2O3, mean diameter = 8.6 nm) dispersed in glycerin at a volume fraction of ~15%. The low temperature aging behavior has been explored through ‘zero-field cooled magnetization' (ZFCM) relaxation measurements using SQUID magnetometry. The ZFCM response functions were found to scale with effective age of the system in both textured and non-textured superspin glass states, but with markedly different scaling exponents, μ. The value of μ was found to shift from ~0.9 in non-textured case to ~ 0.6 in the textured case, despite the identical cooling protocol used in both experiments.

Domaines: Autre [cond-mat.other]

Sawako Nakamae, Emmanuelle Dubois, Vincent Dupuis, Denis L'Hôte, Régine Perzynski, et al.. Superspin glass aging behavior in textured and nontextured frozen ferrofluid. MMM-Intermag Conference, Jan 2010, United States. pp.09E135, ⟨10.1063/1.3366615⟩. ⟨hal-00486838⟩