STRUCTURAL CHARACTERIZATION OF FE3O4-NIO SUPERLATTICES USING HIGH-RESOLUTION TRANSMISSION ELECTRON-MICROSCOPY

Superlattices of Fe3O4-NiO layers have been studied by high-resolution , transmission electron microscopy (HRTEM). These superlattices are gr own by oxygen-plasma-assisted molecular-beam epitaxy (MBE) on (001) or iented MgO substrates, and exhibit a high degree of ordering at the in terfaces between the interlayers. The lack of misfit dislocations at t he Fe3O4-NiO interfaces suggests that lattice strain is largely accomm odated by changes in the lattice spacing. By quantitative HRTEM analys is of Fe3O4-NiO interfaces,possible atomic models are discussed, havin g implications in magnetic ordering and spin exchange mechanisms for s uch interlayer systems.