Long-Range Ordering of Oxygen-Vacancy Planes in α-Fe₂O₃ Nanowires and Nanobelts

We observed two long-range-ordering structures of oxygen vacancies, one in every tenth plane of (33̅0) and another in every fourth plane of (11̅2) in α-Fe 2 O 3 nanowires and nanobelts synthesized under the same conditions. Interestingly, both types of oxygen-vacancy structures found in different nanowires have an equivalent ordering distance of 1.45 or 1.47 nm and were parallel to the growth direction of the nanowires and nanobelts. Lattice mismatch induced strain at the growth temperatures seems to justify the observed vacancy-ordering distance and may explain the reason for occurrence of such oxygen-vacancy ordering in various metal oxide nanowires grown from using both foils and catalyst clusters.