Dynamics of spin glasses in two dimensions

TL;DR

This paper investigates the dynamics of spin glasses in two dimensions, highlighting how thin film multilayers transition from three-dimensional to two-dimensional behavior over time and how correlation lengths evolve.

Contribution

It demonstrates experimentally that spin glass multilayers exhibit a transition from 3D to 2D dynamics over time, with correlation lengths growing faster in 2D at long times.

Findings

Correlation lengths grow more rapidly in 2D than in 3D.

Long-time dynamics in 2D reach equilibrium in experiments.

Transition from 3D to 2D behavior observed in multilayer systems.

Abstract

Spin glass dynamics is a strong function of spatial dimensionality $D$. The lower critical dimension is close to 2.5, so that, in two dimensions, the condensation temperature $T_\text{g}=0$, and only fluctuations are present at finite temperatures. However, by using thin film multilayers, one can explore the dynamics in both $D=3$ and $D=2$ dimensions. Spin glass thin film multilayers transition from $D=3$ dynamics at short to intermediate times to $D = 2$ dynamics at long times. Correlation lengths of CuMn 4.5 nm multilayers at long times are shown to be grow more rapidly in $D=2$ as compared to $D=3$, and for the longest measurement time, experimentally reach equilibrium in qualitative agreement with simulations.