Observation of the role of subcritical nuclei in crystallization of a glassy solid.
Phase transformation generally begins with nucleation, in which a small aggregate of atoms organizes into a different structural symmetry. The thermodynamic driving forces and kinetic rates have been predicted by classical nucleation theory, but observation of nanometer-scale nuclei has not been possible, except on exposed surfaces. We used a statistical technique called fluctuation transmission electron microscopy to detect nuclei embedded in a glassy solid, and we used a laser pump-probe technique to determine the role of these nuclei in crystallization. This study provides a convincing proof of the time- and temperature-dependent development of nuclei, information that will play a critical role in the development of advanced materials for phase-change memories.
Lee
Bong-Sub
BS
Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign (UIUC), Urbana, IL 61801, USA.
Burr
Geoffrey W
GW
Shelby
Robert M
RM
Raoux
Simone
S
Rettner
Charles T
CT
Bogle
Stephanie N
SN
Darmawikarta
Kristof
K
Bishop
Stephen G
SG
Abelson
John R
JR