Co-precipitated Cobalt Ferrite Research Articles

Annealing Temperature Dependence on Magnetic Properties, Crystalline Structure and Photocatalyst Activity of Coprecipitated Cobalt Ferrite (CoFe2O4) Synthesised from Natural Iron Sand

Cobalt ferrite (CoFe2O4) nanopowder was successfully synthesised by the coprecipitation method. For the entire experiment, natural iron sand from the Bengawan Solo River is used as an iron (Fe) cation source. The effect of the annealing temperature of a coprecipitated CoFe2O4 sample from natural iron sand was investigated. The presence of strong metal oxide bond groups at the tetrahedral and octahedral sites is revealed by fourier transform infrared (FTIR) spectral results, owing to the CoFe2O4 characteristic. Then the X-ray diffraction (XRD) pattern confirmed the formation of a single-phase CoFe2O4 with face centred cubic (FCC) crystal structure closely matched to reference data ICDD221086. The crystalline parameters such as lattice parameter and crystallite size modify with the increase of annealing temperature. The saturation magnetisation (Ms) decreases as the annealing temperature rises. In addition, the coercive fields (Hc) increases as the annealing temperature rises. As a result, the annealing temperature affects the performance of the CoFe2O4 photocatalyst. The photocatalytic performance of the annealing temperature sample at 300°C was found to be the best.

Effect of Temperature Synthesize on the Crystalline Structures and Magnetic Properties in Co-Precipitated Cobalt Ferrite Bismuth Nanoparticles

The synthesis of CoBi0.15Fe1.85O4 obtained from cobalt ferrite doped by bismuth using the coprecipitation method was successfully carried out by varying the temperature of the titration. In this study the temperature of titration was used at 65°C, 75°C, 85°C, and 95°C. Annealing was then carried out at a temperature of 800°C for 5 hours. The results of the synthesis were then characterized using X-Ray Diffractometer (XRD), Fourier Transform Infra-Red (FTIR) and Vibrating Sample Magnetometer (VSM). The increase of the magnetic characterization i.e. the saturation magnetization increases and coercivity attribute the increase of the anisotropy crystalline.

Effect of calcination temperature on structural and magnetic properties in cobalt ferrite nano particles

We discuss the calcination temperature dependence of the structural and magnetic properties of co-precipitated cobalt ferrite. Calcination process was performed under atmospheric condition without inert gas. High-purity cobalt ferrite nanoparticles are obtained experimentally. The size of the crystallites increases with the increase of the calcination temperature. Furthermore, the XRD analysis result show that cation redistribution occurs with the increase of the calcination temperature. The SEM result show that the structural organization of these particles changes from separate nanoparticles to the formation of compact granules with increasing calcination temperature. As a result, the saturation magnetization increases with the calcination temperature, reaching up to 62.30 emu/g. It was found that the cation distribution for both tetrahedral and octahedral sites affected by the calcination temperature.

Effect of doping Strontium ions in co-precipitated cobalt ferrite

The effect of doping strontium in structural and magnetic properties of co-precipitated strontium cobalt ferrite (SrxCo1-xFe2O4) nanoparticles are discussed in this paper. The mole of strontium ions was used for doping are 10% of mole cobalt. The synthesis was conducted at a temperature of 95°C with following post annealing at 600°C for five hours. The result of X-ray diffraction showed that the strongest peak intensity of sample decrease when available strontium ions doping. The crystallite size decreased from 23.50 to 22.65 nm while the strain increased. The IR spectra of the sample with strontium doping have lower transmittance than the sample without doping. The FTIR result showed that the strontium ions were suppressing the ions in the octahedral site. The magnetic properties showed that coercive field increased and the saturation magnetization decreased with the addition of strontium ions in cobalt ferrite nanoparticles.

FTIR and structural properties of co-precipitated cobalt ferrite nano particles

The FTIR and structural properties in co-precipitated cobalt ferrite (CoFe2O4) nanoparticles are discussed in this paper. The synthesis was conducted at temperatures of 75°C and 95°C following post annealing at 1200°C for 5 hours. Other modification samples were synthesis at temperature of 95°C and then annealing at temperature of 1000°C and 1200°C for 5 hours. For both modification of synthesis and annealing temperature, FTIR result showed a metal oxide at a wave number of 590 cm-1 which indicated cobalt ferrite nanoparticles. The crystalline structure was confirmed using x-ray diffraction that the high purity of cobalt ferrite was realized. Calculation of the cation distribution by using comparison I220/I222 and I422/I222 show that the synthesis and annealing temperature succesfully modify cation occupy the site octahedral and tetrahedral.

Coprecipitated Cobalt Ferrite for Sensors

Coprecipitated Cobalt Ferrite for Sensors

Reversible processes in magnetization reversal of co-precipitated cobalt ferrite

A study of the magnetization reversal process in a co-precipitated cobalt ferrite material at 300 K was carried out. The evolution of the reversible M rev and irreversible M irr magnetization components were determined by measuring sets of recoil curves from different points on the initial magnetization curve and demagnetization curve. From these data, M rev( M irr) H i curves were built, being H i the internal field of the sample. The interrelation function η=( M rev/ M irr) H i was determined as well. The results suggest that domain wall movement subject to pinning is the dominant mechanism for the reversal magnetization process in this material.

Time-dependent magnetization in co-precipitated cobalt ferrite

A study of the magnetic aftereffect in co-precipitated cobalt ferrite is presented. Measurements of the magnetic viscosity S were performed at room temperature along the demagnetization curve for different applied fields H ap over a wide range of fields (0 kOe<H ap < - 7kOe). The interrelation function η=(∂M rev /∂M irr ) Hi between the DCD reversible M rev and irreversible M irr magnetization components was determined as well. The experimental results for S η (H i ), where H ι is the internal field, showed a broad distribution with a maximum at H ι = 2.7kOe. However, the irreversible susceptibility X irr displays a maximum at H c = 0.75 kOe, the coercivity of the material. The experimental behavior of η and the non-proportionality between S η and X ι ιrr suggest that the magnetic viscosity in this material is principally supplied by events of nucleation of inverse domains and the depinning of domain walls. When the main mechanism of reversal magnetization changes to rotation of magnetic moments for all the grains, the magnetic viscosity decreases.

Magnetization reversal in co-precipitated cobalt ferrite

A study about the magnetic viscosity and magnetization reversal in co-precipitated cobalt ferrite was carried out. Measurements of direct current demagnetization reversible M rev and irreversible M irr magnetization as well as magnetic viscosity S η were performed at room temperature along the demagnetization curve for different applied fields H ap (0>H ap >−7 kOe) . From these data M rev( M irr) H i curves were built. The experimental results show a minimum in the M rev( M irr) H i curves and a non-proportionality between S η and χ irr, suggesting two different contributions to the reversal magnetization during the demagnetization process.

Reversible-irreversible magnetization processes and remanence properties of coprecipitated cobalt ferrite

Se obtuvo ferrita de cobalto por coprecipitacion de sulfatos de hierro y cobalto en acetona. Usando el modelo movil de Preisach se separaron las componentes reversible (Mrev) e irreversible (Mirr) de la magnetizacion. El parametro �A definido como �A = (dMrev / dMirr)Hi y el parametro movil de Preisach km , se evaluaron mediante la relacion �A = km�Orev para investigar el comportamiento de Mrev Se encontro que �A no es proporcional a la susceptibilidad reversible, por lo tanto, km es una funcion del campo interno. Se midieron las curvas de magnetizacion isotermica remanente (MIR) y de desmagnetizacion (DCD). A partir de los datos MIR y DCD se construyo la curva �Âm y el grafico de Henkel, el cual se encuentra por debajo de la linea de Wohlfarth indicando que domina el desorden local (efecto del tipo desmagnetizante) sobre el efecto de campo medio. Diferenciando las curvas de MIR y DCD se obtuvieron las curvas de distribucion de campos de conmutacion. Los valores pico de estas distribuciones de campos de conmutacion difieren por un factor de 2.7.

Remanence properties of Co-precipitated cobalt ferrite

Isothermal remanent magnetization (IRM) and DC demagnetization (DCD) curves of a co-precipitated cobalt ferrite sample were obtained. From the IRM and DCD data, the Henkel plot was obtained and analyzed in the Preisach model framework. The Henkel plot data are below the Wohlfarth line that indicates a dominant local disorder (demagnetizing-like effect). Forward and reverse switching field distribution curves were obtained from differentiation of the IRM and DCD curves. The peak values of these switching field distributions differ by a factor of about 2.7.

Study of reversible and irreversible magnetization processes of coprecipitated cobalt ferrite

Cobalt ferrite was obtained by coprecipitation of iron and cobalt sulphates into acetone medium. The Co0.62+Fe0.43+[Co0.42+Fe1.63+]O4 cation distribution was obtained from Mössbauer spectroscopy at room temperature. Saturation magnetization of 74.1 emu/g and an intrinsic coercive field of 528 Oe were measured using a vibrating sample magnetometer. Using the moving Preisach model, separation of reversible (Mrev) and irreversible (Mirr) magnetization components was performed. The parameters η defined as η=(dMrev/dMirr)Hi and km the moving Preisach parameter expressed through the relation η=kmχrev, were evaluated in order to investigate the hysteretic behavior of Mrev. Additional characterization was done in order to investigate the elemental composition, structure, and morphology of the samples.