The structural and magnetic properties of dual phase cobalt ferrite

Abstract

The bismuth (Bi3+)-doped cobalt ferrite nanostructures with dual phase, i.e. cubic spinel with space group Fd3m and perovskite with space group R3c, have been successfully engineered via self-ignited sol-gel combustion route. To obtain information about the phase analysis and structural parameters, like lattice constant, Rietveld refinement process is applied. The replacement of divalent Co2+ by trivalent Bi3+ cations have been confirmed from energy dispersive analysis of the ferrite samples. The micro-structural evolution of cobalt ferrite powders at room temperature under various Bi3+ doping levels have been identified from the digital photoimages recorded using scanning electron microscopy. The hyperfine interactions, like isomer shift, quadrupole splitting and magnetic hyperfine fields, and cation distribution are confirmed from the Mossbauer spectra. Saturation magnetization is increased with Bi3+-addition up to x = 0.15 and then is decreased when x = 0.2. The coercivity is increased from 1457 to 2277 G with increasing Bi3+-doping level. The saturation magnetization, coercivity and remanent ratio for x = 0.15 sample is found to be the highest, indicating the potential of Bi3+-doping in enhancing the magnetic properties of cobalt ferrite.

Sol–gel auto-combustion mediated cobalt ferrite nanoparticles: a potential material for antimicrobial applications

“…Recently, a size and shape-dependent bactericidal properties of NPs have been explored [16,17] which has endowed an increasing interest in the synthesis method of NPs as it plays a crucial role in determining the physicochemical properties of NPs. Several synthesis methods such as co-precipitation [18], hydrothermal [19], micro-emulsion [20], spray pyrolysis [21], and sol-gel auto-combustion [22], etc., have successfully been addressed in the literature for developing ferrites of different structures and morphologies. Among these, sol-gel auto-combustion method is found to be more suitable for the fabrication of ferrite NPs on a mass scale with desired sizes and shapes.…”

“…These CoFe 2 O 4 NPs were applied in antibacterial efficiency on selected pathogen using agar well-diffusion technique and studied for membrane integrity by membrane leakage assay. O] with addition of citric acid as reducing agent by sol-gel autocombustion method, following the protocol described by Gore et al [22]. Stoichiometric amounts of said chemicals were added into distilled water and pH of the solution was adjusted to 7 using ammonia solution.…”

Specific Loss Power of Co/Li/Zn-Mixed Ferrite Powders for Magnetic Hyperthermia

“…However, the reactions used to synthesize the particles The experimental lattice parameter (a exp ) values of the ferrite phases obtained from the Rietveld refinement of the XRD data are given in Table 1; the value of the Zn-ferrite sample results is higher than the ones of the LiZn-ferrite and CoZn-ferrite samples. This observed increase was due to the replacement of the Co 2+ and Li + ions characterized by an ionic radius of 0.78 and 0.70 Å, respectively, with the bigger Zn 2+ ions (0.83 Å) [63][64][65], in agreement with Vegard's law [66]. Moreover, the X-ray density (ρ XRD ) for each sample was calculated by using the lattice parameter (a exp ) and the standard formula [67]; the obtained values, ranging in the typical interval of this kind of ferrites [33,68], are given in Table 1.…”

Improved Organic Dye Degradation Using Highly Efficient MXene Composites

“…Previous reports on BFO/graphene nanohybrids have also shown higher surface area and higher photogeneration/lower recombination rate that in turn provided the higher photocatalytic activity. [16,19,20,44] The enhanced photocatalytic activity is due to the higher charge carrier generation/lower electron hole recombination rate and possibly higher surface area, thus providing plenty number ofactivated sites on the sheets for the reactions to take place.…”

“…Since the UV and visible lights constitute 3-5 % & 43% of the solar light spectrum respectively [13][14][15], developing new materials which can be used for photocatalysis under visible light irradiation are of great interests. Consequently, bismuth ferrites, BiFeO3 (called BFO hereafter) is a semiconductor material that can work as a promising candidate for photocatalysis using visible light irradiation due to the narrow band gap (~2.2 eV) [16][17][18]. The band gap in BFOs can be improved using doping with other ions [18,19], which alternatively can also improve the photocatalytic activity of BFOs under the visible light irradiation.…”