We explore the feasibility of growing epitaxial $\mathrm{Ti}$-doped $\alpha \text{−}{\mathrm{Fe}}_2{\mathrm{O}}_3$ hematite in which $\mathrm{Ti}\left(\mathrm{IV}\right)$ substitutes for $\mathrm{Fe}\left(\mathrm{III}\right)$ preferentially in one magnetic sublattice but not the other. Such a structure has been predicted by first-principles theory to be energetically favorable, and is expected to yield interesting and useful magnetic and electronic properties. However, we find experimentally that a majority of $\mathrm{Ti}$ dopants disperse and occupy random cation sites in both magnetic sublattices. Density functional theory predicts that the magnetically ordered and magnetically random structures are nearly isoenergetic.

• Received 16 August 2006

DOI:https://doi.org/10.1103/PhysRevB.75.104412