Projects per year
The structure of the fragile glass-forming material CaAl2O4 was measured by applying the method of neutron diffraction with Ca isotope substitution to the laser-heated aerodynamically levitated liquid at 1973(30) K and to the glass at 300(1) K. The results, interpreted with the aid of molecular dynamics simulations, reveal key structural modifications on multiple length scales. Specifically, there is a reorganization on quenching that leads to an almost complete breakdown of the AlO5 polyhedra and threefold coordinated oxygen atoms present in the liquid, and to their replacement by a predominantly corner-sharing network of AlO4 tetrahedra in the glass. This process is accompanied by the formation of branched chains of edge and face-sharing Ca-centered polyhedra that give cationic ordering on an intermediate length scale, where the measured coordination number for O around Ca is 6.0(2) for the liquid and 6.4(2) for the glass.
5/06/12 → 4/10/15
Project: Research council
Drewitt, J. W. E., Hennet, L., Zeidler, A., Jahn, S., Salmon, P. S., Neuville, D. R., & Fischer, H. E. (2012). Structural transformations on vitrification in the fragile glass-forming system CaAl2O4. Physical Review Letters, 109(23), . https://doi.org/10.1103/PhysRevLett.109.235501