TITLE:
Low-Temperature Synthesis of Nanocrystalline Mn0.2Ni0.8Fe2O4 by Oxalate Precursor Route
AUTHORS:
Mahmoud M. Hessien, Zaki I. Zaki, Al-Qahtani Mohsen
KEYWORDS:
Ni-Mn Ferrite; Crystal Structure; Soft Magnets; Oxalate Precursor Route; Magnetic Properties
JOURNAL NAME:
Advances in Materials Physics and Chemistry,
Vol.3 No.1A,
April
26,
2013
ABSTRACT:
Manganese nickel ferrite (Mn0.2Ni0.8Fe2O4)
powder was synthesized through oxalate precursor route. The effect of annealing
temperature (400℃ - 1100℃) on the formation, crystalline size, morphology and
magnetic properties was systematically studied. The resultant powders were
investigated by thermal analyzer (TG-DTG-DSC), X-ray diffractometer (XRD), scanning
electron microscopy (SEM) and vibrating sample magnetometer (VSM). Based on thermal
analysis results, the oxalate mixture decomposed thermally in multisteps weight
loss up to about 680℃. XRD indicated that Mn0.2Ni0.8Fe2O4 formed at much lower annealing temperature (≤400℃) but contained α-Fe2O3 impurity. The
hematite phase decreased by increasing the annealing temperature. The lattice parameters
were increased with increasing annealing temperature up to 1000℃. The average crystalline
size increased by increasing the annealing temperature. Single well
crystalline ferrite was obtained at 800℃with crystallite size about 109 nm. The
saturation magnetization of the ferrites powders continuously increased with the
increase in annealing temperature. Maximum saturation magnetization 48.2 emu/g was
achieved for the formed Mn0.2Ni0.8Fe2O4 phase at annealing temperature
1100℃.