Abstract
We have studied the effect of reducing the particle size on the crystal structures of copper oxide and cerium oxide. Below 25 nm, the cubic O is found to be more stable than the monoclinic CuO. This confirms an earlier conjecture that the ionic character of a solid tends to increase with a reduction in the particle size. As a result, high-symmetry crystal structures are more likely to be stable at smaller sizes. For cerium oxide, the bulk (cubic) phase remains stable down to 4.8 nm and, as expected, does not undergo a transition to any of the other available structures with lower symmetry. © 1996 The American Physical Society.
- Received 18 September 1995
DOI:https://doi.org/10.1103/PhysRevB.53.2167
©1996 American Physical Society