In our present work, magnetic cobalt ferrite (CoFe2O4) nanoparticles have been successfully synthesised by thermal decomposition of Fe(III) and Co(II) acetylacetonate compounds in organic solvents in the presence of oleic acid (OA)/ oleylamine (OLA) as surfactants and 1,2-hexadecanediol (HDD) or octadecanol (OCD-ol) as an accelerating agent. As a result, CoFe2O4 nanoparticles of different shapes were tightly controlled in size (range of 4-30 nm) and monodispersity (standard deviation only at ca. 5%). Experimental parameters, such as reaction time, temperature, surfactant concentration, solvent, precursor ratio, and accelerating agent, in particular, the role of HDD, OCD-ol, and OA/OLA have been intensively investigated in detail to discover the best conditions for the synthesis of the above magnetic nanoparticles. The obtained nanoparticles have been successfully applied for producing oriented carbon nanotubes (CNTs), and they have potential to be used in biomedical applications.

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Spinel cobalt ferrite in the form of nearly spherical particles, having a narrow range of particle size around 7.6nm, was produced by forced hydrolysis. Between the magnetization blocking temperature of 180K and the Mössbauer blocking temperature of 270K, the magnetic anisotropy energy decreases rapidly with temperature. The occupancy of the octahedral sites by only half of the Co2+ cations may have weakened the crystalline anisotropy. Significant spin canting was also observed at these sites.