Synthesis and magnetic properties of cobalt ferrite (CoFe2O4) nanoparticles prepared by wet chemical route

Abstract

Magnetic nanoparticles of cobalt ferrite have been synthesized by wet chemical method using stable ferric and cobalt salts with oleic acid as the surfactant. X-ray Diffraction (XRD) and Transmission Electron Microscope (TEM) confirmed the formation of single phase cobalt ferrite nanoparticles in the range 15-48nm depending on the annealing temperature and time. The size of the particles increases with annealing temperature and time while the coercivity goes through a maximum, peaking at around 28nm. A very large coercivity (10.5kOe) is observed on cooling down to 77K while typical blocking effects are observed below about 260K. The high field moment is observed to be small for smaller particles and approaches the bulk value for large particles. PACS: 75.50Gg; 75.50Tt; 75.70Rf

Preparation of silica coated cobalt ferrite magnetic nanoparticles for the purification of histidine-tagged proteins

“…Cobalt ferrite nanoparticles, which have formulation of CoFe 2 O 4, were synthesized by co-precipitation method (Maaz, Mumtaz, Hasanain, & Ceylan, 2007). The reactions regarding cobalt ferrite synthesis were given in the following equation.…”

“…(Maaz, Mumtaz, Hasanain, & Ceylan, 2007). After obtaining the nanoparticles, washing process with ethanol and water was applied and precipitate was smashed and put in de-ionized water and it was vortexed.…”

An Overview on Nanocrystalline ZnFe2O4, MnFe2O4, and CoFe2O4 Synthesized by a Thermal Treatment Method

“…The decrease in saturation magnetization of all the samples compared to that of the bulk is ascribed to the surface effects in these nanoparticles. The existence of an inactive magnetic layer or a disordered layer on the surfaces of the nanoparticles and the heating rate of calcinations can be due to the decrease of saturation magnetization compared to the bulk value [38,39]. Figure 9 shows the M (H) loops of precursor and CoFe 2 O 4 nanoparticles that were measured at room temperature.…”

Synthesis and magnetic properties of nanocomposite Ni1−x Co x Fe2O4–BaTiO3 fibers by organic gel-thermal decomposition process

“…With a further increase of calcination temperature over 1,100°C, the coercivity then exhibits a reduction tendency as the Ni 0.5 Co 0.5 Fe 2 O 4 grain size is larger than the single-domain size and the particles become multidomains. The domain-wall motions taking place in these multi-domain particles will result in the coercivity reduction [27]. It can be reasoned that the single-domain size of Ni 0.5 Co 0.5 Fe 2 O 4 in the nanocomposite Ni 0.5 Co 0.5 Fe 2 O 4 -BaTiO 3 fibers is around 65 nm, which is close to the value 70 nm for CoFe 2 O 4 particles reported by Rashada et al [28] and 100 nm for NiFe 2 O 4 particles reported by Yao et al [29].…”