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Nanocrystalline/Nanosized Ni 1−γ Fe 2+γ O 4 Ferrite Obtained by Contamination with Fe During Milling of NiO – Fe 2 O 3 Mixture. Structural and Magnetic Characterization
Author(s) -
Marinca Traian F.,
Chicinaş Ionel,
Isnard Olivier,
Popescu Violeta
Publication year - 2013
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.12043
Subject(s) - nanocrystalline material , spinel , materials science , ferrite (magnet) , nickel , magnetization , annealing (glass) , analytical chemistry (journal) , fourier transform infrared spectroscopy , chemical engineering , metallurgy , chemistry , nanotechnology , magnetic field , composite material , chromatography , physics , quantum mechanics , engineering
The nanocrystalline nickel ferrite ( NiFe 2 O 4 ) was synthesized by reactive milling starting from equimolar mixture of oxides. The iron contamination during milling leads to a solid state reaction between Fe and NiFe 2 O 4 spinel. This reaction starts for a milling time longer than 30 h. A mixed nickel–iron ferrite ( Ni 1−γ Fe 2+γ O 4 ) and elemental Ni are obtained. The evolution of the nickel–iron mixed ferrite during milling and its properties were investigated using X ‐ray diffraction, Fourier Transform Infrared Spectroscopy ( FTIR ), Laser Particles Size Analyzer and magnetic measurements. Annealing treatment (350°C/4 h in vacuum) is favorable to the reaction between phases. Replacement of Ni 2+ cations by iron cations provided by contamination leads to the increase of lattice parameter value of the spinel structure. The magnetization of the nickel–iron mixed ferrite newly formed is larger than the nickel ferrite magnetization (13.6 μ B /f.u. and 6.22 μ B /f.u., respectively), due to the magnetic moment of Fe 2+ cation which is double as compared to the Ni 2+ cation. Magnetization of the milled samples decreases during milling due to the structural changes induced by milling in the nickel–iron mixed ferrite. The annealing induces a reordering of the cations which leads to a larger magnetization.