TITLE:
Structural and Magnetic Properties of Monophasic Maghemite (γ-Fe2O3) Nanocrystalline Powder
AUTHORS:
Juan Adrián Ramos Guivar, Arturo Isaías Martínez, Ana Osorio Anaya, Luis De Los Santos Valladares, Lizbet León Félix, Angel Bustamante Dominguez
KEYWORDS:
Monophasic Nanomaghemite, Rietveld Refinement, TEM, SAED, M-H Loops, ZFC
JOURNAL NAME:
Advances in Nanoparticles,
Vol.3 No.3,
August
28,
2014
ABSTRACT: Structural and magnetic
studies of monophasic maghemite (γ-Fe2O3)
magnetic nanocrystallites (MNCs) synthesized by the co-precipitation chemical
route are reported in this paper. For the synthesis, a starting precursor of
magnetite (Fe3O4)
in basic medium was oxidized at room temperature by adjusting the pH = 3.5
at 80°C in an acidic medium without surfactants. X-ray diffraction (XRD)
pattern shows widened peaks indicating nanometric size and Rietveld Refinement confirms
only one single-phase assigned to γ-Fe2O3 MNCs. High Resolution Transmission Electron Microscopy (HR-TEM) demonstrates
the formation of nanoparticles with diameter around D ≈ 6.8 ± 0.1 nm which is in good agreement with Rietveld Refinement
(6.4 ± 1 nm). A selected area electron diffraction pattern was carried out to
complement the study of the crystalline structure of the γ-Fe2O3 MNCs. M(H) measurements taken
at different temperatures show almost zero coercivity and remanence indicating
superparamagnetic domain and high magnetic saturation.