Materials Science-Poland · 2012 · 12 citations · 14 references
Natural SciencesMaterials EngineeringMaterials ScienceInorganic ChemistryMagnetic MaterialsMaterials ChemistryFerrimagnetic MaterialsIron OxidesMagnetic CeramicsMagnetic CharacterizationMagnetic OxidesMagnetic Properties Of SolidsCrystallite Size AnalysisCrystallite Size DeterminationFerritesMagnetic Oxide NanoparticlesMagnetic PropertiesSol-gel SynthesisSol-gel TransitionX-ray Diffraction Analysis
Cobalt ferrite (CoFe2O4) was synthesized using sol-gel techniques from cobalt nitrate: iron nitrate: polyvinyl alcohol (PVA) gel in a ratio of 1:2:12. Variations in the amount of PVA in water (5 %, 10 % and 15 %) influenced the crystallite size and phases of the ferrite products, which in turn controlled their magnetic properties. X-ray diffraction studies indicated single phase CoFe2O4 with larger crystallite size and with the hysteresis loops displaying an increase in both coercive field and squareness as the PVA content was increased. Differential scanning calorimetry (DSC) showed that desorption of water and combustion of excess gel were clearly observed in CoFe2O4 prepared from 10 % and 15 % PVA in water. In the case of 5 % PVA in water, two other ratios of cobalt nitrate: iron nitrate: PVA solution were also tested and it was found that the 1:2:10 ratio led to the smallest coercive field and squareness.
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