Dynamics of Glasslike Transitions in a Quasi-Two-Dimensional System

Abstract

Transverse self-diffusion of field-induced magnetic colloidal chains is measured using real-space imaging. It has been found that the mean-square displacement $〈\Delta r^2〉$ depends on the aligning field $H$ and displays two different behaviors. In short times $〈\Delta r^2〉$ is subdiffusive, whereas in long times $〈\Delta r^2〉$ exhibits normal diffusion. The characteristic time separating the two time regimes diverges exponentially with $H$, indicating fast frozen-in density fluctuations in the system. Our experimental results deviate significantly from the predictions of mode-coupling theory.