From Linear to Nonlinear Response in Spin Glasses: Importance of Mean-Field-Theory Predictions

V. S. Zotev; R. Orbach

doi:10.1103/PhysRevB.66.014412

paper

From Linear to Nonlinear Response in Spin Glasses: Importance of Mean-Field-Theory Predictions

arXiv:cond-mat/0112489 · doi:10.1103/PhysRevB.66.014412

Abstract

Deviations from spin-glass linear response in a single crystal Cu:Mn 1.5 at % are studied for a wide range of changes in magnetic field, $Δ H$ . Three quantities, the difference $T R M - (M F C - Z F C)$ , the effective waiting time, $t_{w}^{e f f}$ , and the difference $T R M (t_{w}) - T R M (t_{w} = 0)$ are examined in our analysis. Three regimes of spin-glass behavior are observed as $Δ H$ increases. Lines in the $(T, Δ H)$ plane, corresponding to ``weak'' and ``strong'' violations of linear response under a change in magnetic field, are shown to have the same functional form as the de Almeida-Thouless critical line. Our results demonstrate the existence of a fundamental link between static and dynamic properties of spin glasses, predicted by the mean-field theory of aging phenomena.

9 pages, 10 figures