MAGNETIC-STRUCTURE DETERMINATION FOR FE3O4 NIO SUPERLATTICES/

Neutron diffraction measurements reveal the nature of the magnetic str ucture in Fe3O4/NiO superlattices grown by molecular beam epitaxy. Tak ing advantage of differences between the Fe3O4 and NiO crystalline sym metries, we have determined independently the magnetic order parameter s of the bilayer components. The NiO antiferromagnetic order propagate s coherently through several superlattice bilayers, while the magnetic coherence of the ferrimagnetic Fe3O4 is restricted to a single interl ayer due to the random stacking of the spinel unit cells at the interf aces. A model for the diffraction data, based upon a Hendricks-Teller description of the interfacial disorder, demonstrates that the observe d broadening of selected reflections originates directly from these st acking faults.