Structural investigation of MFe2O4 (M = Fe, Co) magnetic fluids - Jacintho, Guilherme Vianna de Melo; Brolo, Alexandre Guimaraes; Corio, Paola; Suarez, Paulo Anselmo Ziani; Rubim, Joel Camargo (Journal of Physical Chemistry C : Nanomaterials, Interfaces, and Hard Matter, 2009)