Exchange interparticle interactions in Fe oxides

Spin reorientation in α-Fe2O3 nanoparticles induced by interparticle exchange interactions in α-Fe2O3/NiO nanocomposites.
C. Frandsen, K. Lefmann, B. Lebech, C. R. H. Bahl, E. Brok, S. N. Ancoña, L. Theil Kuhn, L. Keller,T. Kasama, L. C. Gontard, and S. Mørup
Phys. Rev. B 84, 214435 (2011)

Mössbauer spectra of 8-nm α-Fe2O3 nanoparticles obtained at the indicated temperatures; (a) ferrofluid sample, (b)
powder sample, and (c) mixed with NiO nanoparticles