Mössbauer spectra of 8 nm hematite (α-Fe2O3) nanoparticles obtained at the indicated temperatures. (a) Noninteracting hematite particles coated with oleic acid and in aqueous suspension. (b) Hematite particles mixed with NiO. The spectra of the α-Fe2O3/NiO nanocomposite were fitted with two sextets, as shown in panel (b). Reproduced with permission from Frandsen et al. [16].
