Direct View on Non‐Equilibrium Heterogeneous Dynamics in Glassy Nanorods

Abstract

Amorphous solids are potential candidates for room temperature applications, such as structural materials, due to their outstanding mechanical properties. For the first time, the local atomic dynamics of amorphous metallic nanorods are spatially resolved at room temperature using electron microscopy. Methodologically, quasi-equilibrium conditions are verified by two-time correlation functions. FeNiP is chosen as a suitable model system since a bamboo structure forms upon electrodeposition into nanotubular confinement, consisting of thin Fe-rich and Ni-rich amorphous layers. Therefore, the present nano-glassy structure allows studying the glass dynamics of two glassy phases at once, at the same time avoiding any preparation-related structural artifacts of the intrinsically electron-transparent samples. By comparing the local atomic mobility with the local composition and the local structural information of the glassy phases, correlations between medium-range order and time scales of heterogeneous glassy dynamics are consistently obtained.

Structure-Dynamics Relation in Metallic Glass Revealed by 5-Dimensional Scanning Transmission Electron Microscopy

“…Since atomic motion is affected by the surrounding atomic structure, there must be a relation between them. Such a relation has been suggested, 8,[14][15][16] but has not been confirmed experimentally so far, possibly because of the scarcity lack of observation methods that can simultaneously probe both the structural and dynamic heterogeneities. Those methods require a spatial resolution of a few nanometers, a time resolution of a few seconds, and the ability to measure the local structure of glass.…”