Doped Cobalt Ferrite Research Articles

Role of Ni concentration on structural and magnetic properties of inverse spinel Ferrite

In present work, Nickel (Ni) substituted Mn-Co ferrite nanoparticles, with doping content varying from 0 to 0.1, have been synthesized. The inverse spinel structure of doped cobalt ferrite has been claimed by X-ray diffractometer with average particle size of 20 nm. The decrease in lattice parameter and increase in X-ray density has been found with increase in Ni concentration in ferrite structure. Fourier transform infrared spectroscopy analysis showed two vibrational frequency bands (υ1 and υ2) for octahedral and tetrahedral sites depicting the formation of spinel ferrite. In addition, Transmission electron microscopy analyses were carried out to investigate particle size, which indicates that TEM and XRD analyses are in agreement. Magnetic analyses depict that coercivity value increases from 635 Oe to 841 Oe in Ni doped Mn-Co ferrite. Exchange interactions between Ni and Mn0.2Co0.8-xFe2O4 result for enlargement in coercivity and shift in hysteresis loop towards positive direction along the field axis. The increment in magnetic coercive field and exchange bias has been observed as temperature decreases. Enhanced magnetic properties at low temperature are attributed to magneto-crystalline anisotropy and surface effects.

The Properties of Mn, Ni, and Al Doped Cobalt Ferrites Grown by Sol-Gel Method

The manganese-, nickel-, and aluminum-doped cobalt ferrite powders, Mn0.2Co0.8Fe2O4, Ni0.2Co0.8Fe2O4, and Al0.2CoFe1.8O4, are fabricated by the sol-gel method, and the crystallographic and magnetic properties of the powders are studied in comparison with those of CoFe2O4. All the ferrite powders are nano-sized and have a single spinel structure with the lattice constant increasing in Mn0.2Co0.8Fe2O4 but decreasing in Ni0.2Co0.8Fe2O4 and Al0.2CoFe1.8O4. All the Mössbauer spectra are fitted as a superposition of two Zeeman sextets due to the tetrahedral and octahedral sites of the Fe3+ ions. The values of the magnetic hyperfine fields of Ni0.2Co0.8Fe2O4 are somewhat increased in the A and B sites, while those of Mn0.2Co0.8Fe2O4 and Al0.2CoFe1.8O4 are decreased. The variation of Mössbauer parameters is explained using the cation distribution equation, superexchange interaction and particle size. The hysteresis curves of the ferrite powders reveal a typical soft ferrite pattern. The variation in the values of saturation magnetization and coercivity are explained in terms of the site distributions, particle sizes and the spin magnetic moments of the doped ions.

Evaluation of structural and dielectric properties of Al, Ce co-doped cobalt ferrites

The structural and electrical properties of undoped CoFe2O4 and Co1−xAlxFe1.8Ce0.2O4 (x = 0.3, 0.4 and 0.5) samples synthesized by sol-gel method is reported in this paper. The prepared ferrites were found to crystallize in cubic spinel structure as confirmed by x-ray diffraction study. Al substitution has resulted in appreciable decrease in the crystallites size. The dielectric constant (ε′), dielectric loss factor and AC conductivity of nanocrystalline cobalt ferrites were investigated as a function of frequency. Co0.95Al0.5Fe1.8Ce0.2O4 sample is found to exhibit better dielectric properties compared to the other doped and undoped CoFe2O4, Impedance spectroscopy was utilized to analyze the microstructural contribution towards conduction, which confirms the dominance of the grain boundary effect. It is observed that increase in Al doping results in decrease of impedance z′ owing to the relaxation process. Reduced dielectric loss values were observed for these ferrites. Thus Al-Ce doped cobalt ferrites with low loss find potential application in high frequency read/write memory devices.

Investigation on the structures and magnetic properties of carbon or nitrogen doped cobalt ferrite nanoparticles

Carbon or nitrogen doped cobalt ferrite nanoparticles were synthesized in the air by a facile calcination process. X-ray diffraction, mapping, X-ray photoelectron spectroscopy, and mössbauer spectra results indicate that the nonmetal elements as the interstitial one are doped into cobalt ferrite nanoparticles. The morphologies of doped cobalt ferrite nanoparticles change from near-spherical to irregular cubelike shapes gradually with the increased carbon or nitrogen concentration, and their particles sizes also increase more than 200 nm. Furthermore, the saturation magnetization of carbon doped cobalt ferrite is improved. Although the saturation magnetization of N-doped cobalt ferrite is not enhanced obviously due to the involved hematite, they also do not drop drastically. The results reveal an approach to synthesize large scale ferrite nanoparticles, and improve the magnetic properties of ferrite nanoparticles, and also provide the potential candidates to synthesis co-doped functional magnetic materials.

P-A4 Multimodal theranostic tests for antiretroviral drug delivery

Abstract: Long acting slow effective release antiretroviral therapy (LASER ART) was developed to improve patient regimen adherence, prevent new infections and facilitate drug entry into human immunodeficiency viral reservoirs. To speed LASER ART development “multimodal imaging theranostic nanoprobes” were created. These europium (Eu3+) doped cobalt ferrite (CF) dolutegravir (DTG) (EuCF-DTG) nanoparticles were used as platforms for drug-particle biodistribution. After parenteral injection of EuCF-DTG, to rats and rhesus macaques, measured drug and cobalt levels by florescence and magnetic resonance imaging tests were found to be coordinate to iron levels. Moreover, EuCF-DTG was found to be a log order-of-magnitude more sensitive than equivalent amounts of particle encased iron oxide. Folic acid decoration facilitated drug particle cell uptake. We posit that theranostic nanoprobes can facilitate LASER ART drug delivery and be used as part of a precision nanomedicine treatment strategy.

Multimodal Theranostic Nanoformulations Permit Magnetic Resonance Bioimaging of Antiretroviral Drug Particle Tissue-Cell Biodistribution.

RATIONALE: Long-acting slow effective release antiretroviral therapy (LASER ART) was developed to improve patient regimen adherence, prevent new infections, and facilitate drug delivery to human immunodeficiency virus cell and tissue reservoirs. In an effort to facilitate LASER ART development, “multimodal imaging theranostic nanoprobes” were created. These allow combined bioimaging, drug pharmacokinetics and tissue biodistribution tests in animal models.METHODS: Europium (Eu3+)- doped cobalt ferrite (CF) dolutegravir (DTG)- loaded (EuCF-DTG) nanoparticles were synthesized then fully characterized based on their size, shape and stability. These were then used as platforms for nanoformulated drug biodistribution.RESULTS: Folic acid (FA) decoration of EuCF-DTG (FA-EuCF-DTG) nanoparticles facilitated macrophage targeting and sped drug entry across cell barriers. Macrophage uptake was higher for FA-EuCF-DTG than EuCF-DTG nanoparticles with relaxivities of r2 = 546 mM-1s-1 and r2 = 564 mM-1s-1 in saline, and r2 = 850 mM-1s-1 and r2 = 876 mM-1s-1 in cells, respectively. The values were ten or more times higher than what was observed for ultrasmall superparamagnetic iron oxide particles (r2 = 31.15 mM-1s-1 in saline) using identical iron concentrations. Drug particles were detected in macrophage Rab compartments by dual fluorescence labeling. Replicate particles elicited sustained antiretroviral responses. After parenteral injection of FA-EuCF-DTG and EuCF-DTG into rats and rhesus macaques, drug, iron and cobalt levels, measured by LC-MS/MS, magnetic resonance imaging, and ICP-MS were coordinate.CONCLUSION: We posit that these theranostic nanoprobes can assess LASER ART drug delivery and be used as part of a precision nanomedicine therapeutic strategy.

Sonochemical synthesis of Gd3+ doped CoFe2O4 spinel ferrite nanoparticles and its physical properties

In this work, a facile and green method for gadolinium doped cobalt ferrite (CoFe2−xGdxO4; x=0.00, 0.05, 0.10, 0.15, 0.20) nanoparticles by using ultrasonic irradiation was reported. The impact of Gd3+ substitution on the structural, magnetic, dielectric and electrical properties of cobalt ferrite nanoparticles was evaluated. The sonochemically synthesized spinel ferrite nanoparticles were characterized by X-ray Diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM). X-ray diffraction (XRD) study confirmed the formation of single phase spinel ferrite of CoFe2−xGdxO4 nanoparticles. XRD results also revealed that ultrasonic irradiation seems to be favourable to achieve highly crystalline single crystal phase gadolinium doped cobalt ferrite nanoparticles without any post annealing process. Fourier Transform Infrared and Raman Spectra confirmed the formation of spinel ferrite crystal structure. X-ray photoelectron spectroscopy revealed the impact of Gd3+ substitution in CoFe2O4 nanoparticles on cation distribution at the tetrahedral and octahedral site in spinel ferrite crystal system. The electrical properties showed that the Gd3+ doped cobalt ferrite (CoFe2−xGdxO4; x=0.20) exhibit enhanced dielectric constant (277 at 100Hz) and ac conductivity (20.2×10−9S/cm at 100Hz). The modulus spectroscopy demonstrated the impact of Gd3+ substitution in cobalt ferrite nanoparticles on grain boundary relaxation time, capacitance and resistance. Magnetic property measurement revealed that the coercivity decreases with Gd3+ substitution from 234.32Oe (x=0.00) to 12.60Oe (x=0.05) and further increases from 12.60Oe (x=0.05) to 68.62Oe (x=0.20). Moreover, saturation magnetization decreases with Gd3+ substitution from 40.19emu/g (x=0.00) to 21.58emu/g (x=0.20). This work demonstrates that the grain size and cation distribution in Gd3+ doped cobalt ferrite nanoparticles synthesized by sonochemical method, is effective in controlling the structural, magnetic, and electrical properties, and can be find very promising applications.

Colossal piezomagnetic response in magnetically pressed Zr+4 substituted cobalt ferrites

A remarkable 111% increase in magnetostriction (λ) and 435% increase in strain sensitivity (dλ/dH) (compared to normally compacted (NC) unsubstituted CoFe2O4 (CFO)) of Zr+4 doped CFO sample, Co1.2Zr0.2Fe1.6O4, prepared by magnetic field assisted compaction, have been reported in this study. Magnetic field assisted compaction (MC) has been employed to process Zr-doped cobalt ferrites, Co1+xZrxFe2−2xO4 (0 ≤ × ≤ 0.4), to further improve the magnetoelastic properties. Saturation magnetization (MS) and coercivity (HC) increase from ~426 kA/m and ~4.4 kA/m respectively, for x = 0, to ~552 kA/m and ~7.11 kA/m respectively for x = 0.2. Dramatic increase in λ was observed for MC samples (~ −360 ppm and ~−380 ppm for x = 0 and x = 0.2 respectively) compared to the NC samples (~−181 ppm and ~−185 ppm for x = 0 and x = 0.2 respectively). A remarkable quadruple increase in dλ/dH was observed in Zr-doped (x = 0.2) cobalt-ferrite (~4.3 × 10−9 A−1m) compared to that of unsubstituted cobalt-ferrite (~1.24 × 10−9 A−1m), while a fivefold increase in dλ/dH was observed for magnetically compacted (MC) Zr doped cobalt ferrite (x = 0.2) (~4.3 × 10−9 A−1m) compared to normal compacted (NC) unsubstituted cobalt ferrite (~0.8 × 10−9 A−1m).

Photocatalytic removal of rhodamine B under irradiation of visible light using Co1−xCuxFe2O4 (0 ≤ x ≤ 0.5) nanoparticles

Co1−xCuxFe2O4 (0≤x≤0.5) nanoparticles were prepared by the microwave combustion technique. The obtained samples were characterized using X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS), high resolution scanning electron microscopy (HR-SEM), energy dispersive X-ray (EDX) analysis, UV–visible diffuse reflectance spectroscopy, photoluminescence (PL) spectroscopy, Fourier transformed infrared (FT-IR) spectroscopy and vibrating sample magnetometry. The XRD result confirms the formation of cubic spinel structure and the average crystallite size was observed to be in the range of 46–31nm calculated by Debye Scherrer’s equation. XPS analysis was carried out to study the chemical elements and oxidation states of the synthesized Co1−xCuxFe2O4 (0≤x≤0.5) nanoparticles. The HR-SEM image showed agglomerated spherical nanoparticles and the elemental composition of copper doped cobalt ferrite was attained from energy dispersive X-ray analysis. The band gap energy was calculated by diffuse reflectance spectroscopy. Photoluminescence spectra showed the rate of recombination of electron-hole pairs and presence of defects. The band at 661 and 569cm−1 is due to the intrinsic stretching vibrations of octahedral group complex of Co2+–O2− and Fe3+–O2− at tetrahedral sites. Remanence magnetization (Mr), coercivity (Hc) and saturation magnetization (Ms) were deduced from the hysteresis curves. The obtained Co1−xCuxFe2O4 (0≤x≤0.5) nanoparticles were assessed for the photocatalytic degradation of RhB under visible light. A possible mechanism responsible for photocatalytic degradation process is discussed.

Visible light driven photocatalytic degradation of rhodamine B using Mg doped cobalt ferrite spinel nanoparticles synthesized by microwave combustion method

Co1-xMgxFe2O4 (0≤x≤0.5) spinel nanoparticles were synthesized by a simple microwave combustion method. The characterization of the samples were performed using X-ray diffraction (XRD) analysis, scanning electron (SEM) microscopy, energy dispersive X-ray (EDX) analysis, UV–visible and diffuse reflectance (DRS) spectroscopy, photoluminescence (PL) spectroscopy, Fourier transformed infrared (FT-IR) spectroscopy and vibrating sample magnetometry (VSM) analysis. The XRD patterns indicate the formation of cubic inverse spinel structure. The calculated average crystallite size using Debye Scherrer's equation is found to be around 46–38nm. The morphology of spinel nanoparticles was observed from SEM images and the elemental mapping of magnesium doped cobalt ferrite was obtained by using energy dispersive X-ray technique. Optical studies were carried out for the deeper understanding of the conduction band (CB) and valence band (VB) edges of the synthesized nanoparticles. The intrinsic stretching vibrations of Fe3+-O2- in tetrahedral sites leads to the appearance of IR band at around 573cm−1. The magnetic properties such as remanence magnetization (Mr), coercivity (Hc) and saturation magnetization (Ms) were calculated from the hysteresis curves. The maximum photocatalytic degradation efficiency for Co0.6Mg0.4Fe2O4 is around (99.5%) when compared to that of CoFe2O4 whose efficiency is around (73.0%). The improvement in photocatalytic degradation efficiency is due to the effective separation and prevention of electron-hole pair recombination. The R2 values for the first order rate kinetics are found to be better than R2 values for the second order rate kinetics and this proves that photocatalytic degradation of RhB dye follows first order kinetics. The probable mechanism for the photocatalytic degradation of RhB dye is proposed.

Boosting the catalytic performance of pristine CoFe2O4 with yttrium (Y3+) inclusion in the spinel structure

In this work, yttrium doped cobalt ferrite (CoFe2O4) as a magnetic photocatalyst having composition CoYxFe2-xO4 (x=0.0, 0.1, 0.2, 0.3) with excellent catalytic activity was successfully fabricated. The influence of Y3+ doping on structural, optical, magnetic and surface area of all the prepared samples was verified using diverse techniques. The results illustrated formation of crystalline single phase cubic spinel structure with sufficient magnetic temperament (21–65 emu/g) in all the samples. Furthermore, inclusion of Y3+ also altered the band gap (1.15–1.26eV) and BET surface area values (53–79m2/g) of pristine CoFe2O4. The main aim of present work is to alter the catalytic activity of CoFe2O4; hence photo-Fenton reaction was selected, with two different inorganic oxidants. The results demonstrated enhancement in catalytic activity with Y3+ doping in comparison to pure CoFe2O4 irrespective of inorganic oxidant used. Moreover, recyclability of prepared photocatalysts illustrated stability of materials for long term use in wastewater treatment.

Structural, morphological and magnetic properties of Eu-doped CoFe2O4 nano-ferrites

Europium (Eu) doped spinel cobalt ferrites having composition CoEuxFe2−xO4 where x=0.00, 0.03, 0.06, 0.09, 0.12 were fabricated by co-precipitation route. In order to observe the phase development of the ferrite samples, thermo-gravimetric analysis was carried out. The synthesized samples were subjected to X-ray diffraction analysis for structural investigation. All the samples were found to constitute face centered cubic (FCC) spinel structure belonging to Fd3m space group. Scanning electron microscopy revealed the formation of nanocrystalline grains with spherical shape. Energy dispersive X-ray spectra confirmed the presence of Co, Eu, Fe and O elements with no existence of any impurity. The magnetic hysteresis curves measured at room temperature exhibited ferrimagnetic behavior with maximum saturation magnetization (Ms) of 65emu/g and coercivity (Hc) of 966Oe. The origin of ferrimagnetism in Eu doped cobalt ferrites was discussed in detail with reverence to the allocation of Co2+ and Fe3+ ions within the spinel lattice. The overall coercivity was increased (944–966Oe) and magnetization was decreased (65–46emu/g) with the substitution of Eu3+. The enhancement of former is ascribed to the transition from multi domain to single domain state and reduction in lateral is attributed to the incorporation of nonmagnetic Eu ions for Fe, resulting in weak superexchange interactions.

Development of europium doped core-shell silica cobalt ferrite functionalized nanoparticles for magnetic resonance imaging.

A novel europium (Eu3+) doped cobalt ferrite (Si-CFEu) nanoparticle was produced for use as a bioimaging probe. Its notable multifunctional, fluorescence and imaging properties, allows rapid screening of future drug biodistribution. Decoration of the Si-CFEu particles with folic acid increased its sensitivity and specificity for magnetic resonance imaging over a more conventional ultrasmall superparamagnetic iron oxide particles. The future use of these particles in theranostic tests will serve as a platform for designing improved drug delivery strategies to combat inflammatory and infectious diseases.

Photocatalytic degradation of rhodamine B under visible light using nanostructured zinc doped cobalt ferrite: Kinetics and mechanism

Nanostructured Co1-xZnxFe2O4(0≤x≤0.5) catalyst synthesized by the microwave combustion method was employed for the photocatalytic degradation of rhodamine B (RhB) under visible light. Doping of Zn2+ ions in the cobalt ferrite matrices were confirmed by the diffraction peak-shift towards lower angles. The Williamson-Hall method was used to calculate the crystallite size considering the strain components. The conduction band (CB) and valence band (VB) edges of all the samples were calculated using optical studies. Photoluminescence analysis performed at an excitation wavelength of 330nm disclosed the rate of recombination of electron-hole pairs and the defects present. Photocatalytic degradation of RhB with pure cobalt ferrite system was performed at pH 2.0 by varying the time, initial concentration and addition of hydrogen peroxide to behave like a Fenton like process. However the effective photodegradation of all zinc doped cobalt ferrite were done at optimal RhB concentration of 6mg/l at identical operational conditions. Among all the samples Co0.6Zn0.4Fe2O4 exhibited an enhanced degradation efficiency of 99.9% at visible light exposure time of 210min. The degradation pathway followed first order rate rather than the second order rate kinetics. Based on the values of CB and VB edges in the Co0.6Zn0.4Fe2O4 system, possible routes for the degradation of RhB are suggested.

Structural, electronic and magnetic properties of RE3+-doping in CoFe2O4: A first-principles study

RE3+(RE=La, Ce, Pr, Nd, Eu, Gd) doped cobalt ferrite (CoFe2O4) have been studied systematically by the first-principles calculations based on density functional theory within the generalized gradient approximation with Hubbard corrections (GGA+U) . The significant effects of RE3+doping on the crystal structure, electronic and magnetic properties of CoFe2O4 have been explored. The calculated results show that the RE ions prefer substituting Fe3+ located at the octahedral sites. And the lattice constant of CoFe1.875RE0.125O4 (RE=La, Ce, Pr, Nd, Eu and Gd) decreases due to the decreasing ionic radius of RE as the atomic number increases. The magnetic properties depend on the unpaired 4f electrons of RE3+ ions. The net magnetic moment of CoFe2O4 increases by doping with Eu and Gd, the reason is that there are more unpaired 4f electrons for Eu3+and Gd3+. However, the net magnetic moment of CoFe2O4 decreases by doping with La, Ce, Pr, and Nd, due to the reason that these RE ions prefer their low spin configurations.

Functionally graded doped lanthanum cobalt ferrite and ceria-based composite interlayers for advancing the performance stability in solid oxide fuel cell

Abstract Functionally graded composite interlayer based on 50% of La 0.54 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ and 50% of La 0.54 Sr 0.4 Fe 0.2 Co 0.8 O 3-δ (CF-1) and cobalt and gadolinium doped ceria (CoCGO) is synthesized varying the mass ratio as CF-1:CoCGO = 80:20(L80-C20), 50:50(L50-C50) and 20:80(L20-C80). Detail study using impedance spectroscopy of symmetrical cell fabricated with CoCGO as electrolyte reveals the lowest electrode polarization 0.04 Ω cm 2 at 800 °C for L80-C20 composite. Electrode and ohmic polarization is also evaluated configuring the symmetric cell as CF-1/L80-C20||CoCGO||L80-C20/CF-1. Symmetric cell with varying composition of the composite interlayer (L80-C20/L50-C50/L20-C80||CoCGO||L20-C80/L50-C50/L80-C20) shows considerably low electrode polarization of 0.067 Ω cm 2 at 800 °C with activation energy 1.19 eV. Electrochemical performances evaluated using single cell configuration Ni-YSZ||YSZ||CoCGO/L20-C80/L50-C50/L80-C20/CF-1 shows power density as high as 2.03 W cm −2 at 800 °C at 0.7 V. Addition of composite interlayers increases the stability significantly and the voltage degradation is found negligible (0.9%) for first 300 h at a constant load of 0.5 A cm −2 which is further increased to 2.9% for next 300 h. The cell stability is clinically correlated with layer wise elemental ‘Sr’ mapping in the applied quad interlayers.

Enhanced electrical properties in Nd doped cobalt ferrite nano-particles

Spinel ferrites are important class of compounds which has variety of electrical, magnetic and catalytic applications. A small amount of rare earth element causes modification in structural, electrical and magnetic properties of ferrite materials for practical applications. Neodymium doped cobalt ferrites with composition CoNdxFe2-xO4 where x is 0.1 has been synthesized by sol-gel method. Sol-gel method was preferred because it has good control over stoichiometry, crystallite size and particle size distribution. Characterization was done by using X-Ray Diffraction (XRD) technique for structural analysis and crystal structure was found to be spinel. Particles like morphology was observed in micrographs obtained by Scanning Electron Microscopy (SEM). Thermal analysis of sample has been done which includes Thermogravimetric analysis (TGA) and Differential Scanning calorimetry (DSC). Fourier transform infra-red spectroscopy (FT-IR) of samples was also performed. DC resistivity as a function of temperature has been studied and its shows direct dependence on temperature and inverse dependence on the concentration of Nd dopant. The studied material is a potential candidate for resistive random access memory application.

Association of structural and enhanced transport properties in RE substituted cobalt nanoferrites

Spinel ferrites belong to an important class of compounds which has variety of electrical and magnetic applications. Neodymium doped cobalt ferrites with composition CoFe2-xNdxO4 where x = 0.00, 0.05, 0.10, 0.15, 0.20 were synthesized by wet chemical route called simplified sol-gel method. Prepared samples were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) for structural analysis. All the samples were found spinel cubic belonging to Fd-3m space group. To analyze temperature effects on phase transition and to check thermal stability differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were done. Sample with x = 0.00 was found to be thermally more stable than remaining samples. Electrical analysis was done by using two probe method. DC electrical resistivity and drift mobility of sintered samples were measured as a function of temperature in the range from room temperature to 450 °C. It was observed that DC electrical resistivity has a direct dependence on dopant concentration but indirect dependence on temperature. Verwey hopping model was used to describe the results of DC electrical resistivity. Activation energy calculated from linear plots of DC resistivity for all samples was in the range of 0.532–0.594 eV. Rarely reported thermal transport properties that include thermal conductivity, thermal diffusivity and volumetric heat capacity were measured by Advantageous Transient Plane Source (ATPS) method. All the samples showed values near to that of thermal insulators. Thermal conductivity of all samples was increased up to 100–120 °C and then decreased. This behavior was thoroughly studied.

Erratum to: Magnetic Properties of Dysprosium Doped Cobalt Ferrite Nanoparticles Synthesized by Starch-Assisted Sol-Gel Auto-combustion Method

Erratum to: Magnetic Properties of Dysprosium Doped Cobalt Ferrite Nanoparticles Synthesized by Starch-Assisted Sol-Gel Auto-combustion Method

Role of Bismuth in Cobalt Spinel Ferrite

The current project deals with the synthesis and characterization of bismuth doped cobalt ferrite with general formula of CoBixFe(2-x)O4 (where x varies from zero to 0.5 with the step size of 0.1). This series have been prepared using powder metallurgy route. The structural, chemical, morphological, elemental, magnetic and optical properties have been investigated using XRD, FTIR, SEM, EDX, VSM and UV Visible spectrometer respectively. Structural measurements show the confirmation of spinel structure. This also shows the decrease in lattice parameters and crystallite sizes, which are due to the replacement of larger cations Fe+3 by smaller cations Bi+3. Functional groups or characteristic bonds of spinel ferrites have been investigated by FTIR spectrum. SEM micro graphs revealed the spherical shape of the particles, also shows the un-even or non-uniform grain boundaries. An EDX spectrum confirms the elemental composition of the prepared ferrites. UV-Visible spectrometer revealed the increase in band gap with the decrease in grain size. VSM reveals that saturation magnetization decreases with the increase of bismuth oxide content in CoBixFe(2-x)O4.