Synthesis of CoFe2O4 powder via PVA assisted sol–gel process

Abstract

CoFe 2 O 4 ferrites were synthesized by sol-gel method, having metal nitrates as precursors and PVA as surfactant, followed by a heat treatment at 960°C for 2 h. The ultrafine ferrite powders obtained have been characterized by X-ray diffraction, thermal gravimetry, differential scanning calorimetry and room temperature magnetic measurement studies. The morphology of the powder was identified by high resolution-scanning electron microscopy. X-ray diffraction results indicate that the resultant CoFe 2 O 4 crystallites consist of spinel phase. Significant differences in magnetic properties of CoFe 2 O 4 samples synthesized with various concentrations of PVA were observed. The magnetisation measurements show that when the PVA concentration increased, coercivity initially decreased and then increased where as retentivity and magnetisation decreased. The optimum concentration of PVA for the synthesis of CoFe 2 O 4 ferrites is obtained from this investigation. Obviously this material can be used as an efficient candidate for practical recording purpose.

On the origin of remanence enhancement in exchange-uncoupled CoFe2O4-based composites

“…Besides the specific synthesis conditions, the relatively low calcination temperature is a likely reason for the compositional variability, given that temperatures above 900 C are reported to be employed in sol-gel synthesized CFO. 22 As expected, increasing re-annealing at higher temperatures leads to larger particle sizes and homogeneity. From TEM images (not shown), we measure, at 500 C, 700 C, and 900 C, average particle sizes of 68 nm, 80 nm, and 95 nm, respectively.…”

CoFe 2 O 4 magnetic ceramic derived from gel and densified by spark plasma sintering

“…These particles should be nanosized, pure phase and single domain in order to improve their functional properties. For this reason, several papers report on the conditions and methods used for the preparation of cobalt ferrite nanopowders, such as: chemical co-precipitation [2], hydrothermal method, microwave synthesis, sol-gel method [20][21][22], complexometric method [23], polyol method [24] and others. The sol-gel route is one of the most efficient methods to prepare ultra-fine particles with a high purity and homogenous composition [23][24][25].…”

First-Principles Density Functional Theory Characterisation of the Adsorption Complexes of H3AsO3 on Cobalt Ferrite (Fe2CoO4) Surfaces

“…It exhibits remarkably unique and interesting properties such as high saturation magnetisation, high coercivity and anisotropy, good mechanical hardness, chemical stability, and has the highest magnetostriction of all 3d-element-based spinel oxides, with an additional benefit of being cheap and easy to make [13]. The preparation method and conditions of this spinel ferrite strongly influence the acquired degree of inversion and thus its properties [14][15][16][17][18]. In an investigation of the adsorption of both arsenite (H3AsO3) and arsenate (H3AsO4) on Fe2MnO4, Fe2CoO4 and Fe3O4, Zhang et al synthesised the material via co-precipitation, an effective synthetic approach that permits good control of shape and particle size distribution [18,19].…”