Chemical synthesis and magnetic properties of monodisperse cobalt ferrite nanoparticles

Abstract

In this work, a successful synthesis of magnetic cobalt ferrite (CoFe2O4) nanoparticles is presented. The synthesized CoFe2O4 nanoparticles have a spherical shape and highly monodisperse in the selected solvent. The effect of different reaction conditions such as temperature, reaction time and varying capping agents on the phase and morphology is studied.Scanning transmission electron microscopy showed that the size of these nanoparticles can be controlled by varying reaction conditions. Both X-ray diffraction and energy dispersive X-ray spectroscopy corroborate the formation of CoFe2O4 spinel structure with cubic symmetry. Due to optimized reaction parameters, each nanoparticle was shown to be a single magnetic domain with diameter ranges from 6 nm to 16 nm. Finally, the magnetic investigations showed that the obtained nanoparticles are superparamagnetic with a small coercivity value of about 315 Oe and a saturation magnetization of 58 emu/g at room temperature. These results make the cobalt ferrite nanoparticles promising for advanced magnetic nanodevices and biomagnetic applications.

Crucial Role of the Co Cations on the Destabilization of the Ferrimagnetic Alignment in Co-Ferrite Nanoparticles with Tunable Structural Defects

“…For instance, the temperature T p corresponding to the cusp in the ZFC curve, which gives an estimation of the blocking temperature of the particles, rises monotonously along the four samples (Figure a) from 150 K for S1 up to 270 K for S4. The latter compares reasonably well with previous studies of highly crystalline NPs of similar sizes and stoichiometry. ,,− However, T p = 150 K for S1 is much lower than expected for the blocking temperature of 8 nm Co-ferrite particles, suggesting that the effective magnetic volumes being actually blocked are much smaller than the size of the particles. This is a clear indication of the occurrence of more disordered magnetic arrangements in samples with poorer crystalline quality.…”

“…It is worth noting that these values of M max for samples S3 and S4 are only slightly lower than that of the bulk value at room temperature (69 emu·g –1 ), which is a further evidence of their high crystalline quality. ,,− The overall dependence of M max with the samples is shown in Figure b. The occurrence of a higher degree of magnetic disorder and frustration as the particle crystallinity worsens is also evident from the abrupt drop in the H c of the hysteresis loops measured at 5 K, as shown in Figure b.…”

An effective magnetic nanoadsorbent based on a carbonaceous/spinel ferrite nanocomposite for the removal of pharmaceutical pollutants from wastewater

“…04-016-3954). 20 The XRD pattern of the AC–CoFe 2 O 4 nanoadsorbent confirmed that after the introduction of AC, the crystal structure of CoFe 2 O 4 is well preserved. Furthermore, the porosity and surface area ( S BET ) of the CoFe 2 O 4 NPs and AC–CoFe 2 O 4 nanoadsorbent were evaluated by the N 2 adsorption–desorption isotherm as demonstrated in Fig.…”

A controllable one-pot hydrothermal synthesis of spherical cobalt ferrite nanoparticles: synthesis, characterization, and optical properties

“…416 and 590 cm À1 , owing to the vibrational frequencies of Co-O bonds in octahedral sites and Fe-O bonds in tetrahedral sites, respectively, suggesting the formation of the cobalt ferrite NPs phase. [49][50][51] In addition, the bands appeared at ca. 3385 and 1616 cm À1 are related to O-H stretching vibration and H-O-H bending vibration, respectively, originating from moisture and residue of ethylene glycol and Arabic gum.…”