Surface Morphological Characterization of Co_1-xCe_xFe₂O₄ Spinel Ferrites Synthesized by Solid State Reaction Method

The Spinel Ferrite Co _1-xCe _xFe ₂O ₄ with different compositions (x = 0.0, 0.33, 0.66, 1.0) were prepared by solid state reaction method. FTIR (Fourier Transform Infrared Spectroscopy), SEM (Scanning Electron Microscopy) and UV Spectroscopy (Ultraviolet) have been used to study the phase conformation, morphology and structural properties of all synthesized compositions respectively. Lattice constant was observed to be decreased as smaller ionic radii Co ²⁺ (0.74 Å) replaced the higher ionic radii Ce ²⁺ (1.14 Å). FTIR confirm the formation of cubic spinel ferrites by stretching vibration of metal oxide ion mechanism. SEM shows the surface morphology and grain size for synthesized cubic spinel ferrites in the range of 1.25 - 2.65 μm. Opti-cal band gap energy was determined in the range of 1.4575 - 1.425 eV for x = 0.0 to 1.0 nano-ferrites, respectively. This range of band gap energy indicates that the synthesized ferrites have potential applications in electrical devices.

• Ferities
• Co
• Ce
• Structural Properties

1. Introduction

Ferrites, a group of familiar magnetic materials with general formula MFe₂O₄ are extensively applicable in electrical, electronics, medical and industrial applications due to their chemical constancy, economical production cost and improved electric, magnetic and thermal characteristics. Soft ferrites are attractive materials with modest magnetization, greater coactivity, larger anisotropy and fine electrical insulation. Several researchers have explained the optical, electrical, and magnetic properties of zinc ferrite. The electrical and magnetic properties of zinc ferrites can be improved through partial insertion of noble ions such as Cu, Co, Ni, Ce and Mg. SantoshBhukalet, copper-doped CoZn ferrites geared up and detected with a sol-gel auto combustion technique That all nanomaterials are of semiconductor nature [1] . K. Anuet al., synthesized the Zn doped cobalt ferrites by applying two-step process and investigated the variations in electrical and magnetic properties [2] . B.B.V.S. Vera Prasad et al., reported the fabrication of Cu inserted copper zinc ferrites by auto combustion method [3] . They determined the decrease in saturation magnetization with the addition of copper contents. Muhammad Farooq Warsi et al., fabricated erbium doped NiCo spinel ferrites by using co-precipitation route and found the decrease in DC electrical resistivity in the range of 6.20 × 10⁷ - 0.03 × 10⁷ ohm-cm. They observed that these materials are potential candidates for various technological devices. Sandeep b. Somwanshi Al, designed zinc soft ferrites in magnesium and resolved thermal, structural, optical, and spectral characteristics [4] . They concluded an increase in optical bandgap energy in the range of 1.96 - 2.39 eV. Zeeshan Ahmad al, prepared Cerium-doped cobalt ferrites by solid state reaction method and measure the decrease in bandgap energy in the range of 1.4575 - 1.425 eV.

Structural, optical and electrical properties of La³⁺ inserted ZnMgNi soft ferrites were discussed by M.S. Hasan et al., [5] . Careful study of literature exposed that various methods were used by the researchers to synthesise the nanomaterials like co-precipitation, sol gel, hydrothermal, micro emulsion, mechanical milling etc. [6] [7] . Co-precipitation is popular, emerging and economical synthesis method having enormous prospective. Co-precipitation can be employed for the synthesis of complex materials with enhanced functionalities. By incorporating different elements or dopants during the precipitation process, it is possible to modify the properties of the resulting material, such as its magnetic, optical, or catalytic behavior. This opens up opportunities for the development of advanced materials for various technological applications.

2. Result & Discussion

2.1. Result

Characterization techniques which describe the morphology and magnetic behaviour of our materials.

1) UV-VIS

2) FTIR

3) SEM

2.2. UV-VIS Results and Discussion

The optical properties of Co_1−xCe_xFe₂O₄sintered at 800^oC are measured from ultraviolet radiations visible range. As shown in Figure 1.

From the above graph, two absorbance bands are appeared in 600 - 760 nm

Black (x = 0.00) Co_1−xCe_xFe₂O₄

Red (x = 0.33)

Blue (x = 0.66)

Green (x = 1.00)

Figure 1. Representation of Wavelength Vs Absorbance showing Energy band gap.

range. Their analyzed Metal to metal charge transfer transitions (2Fe³⁺ → Fe²⁺ + Fe⁴⁺) and noted that 2a site occupies Fe³⁺ in Co_1−xCe_xFe₂O₄. In other words, the Co²⁺ and Ce²⁺ are introduced in the formula Co_1−xCe_xFe₂O₄ system cause the quantity of iron (Fe³⁺) cat-ions and Fe-O-Fe bonds to decrease, which reduced metal charge transition more difficult [8] . So absorption of Co_1−xCe_xFe₂O₄ composite became weaker. The values of energy band gap for each material are written below Table 1.

2.3. Fourier Transform Infrared Spectroscopy (FTIR)

For the phase confirmation of Co_1−xCe_xFe₂O₄ spinel ferrites, Narrow symmetries in crystalline solids and existence or extinction of Fe²⁺ ions are also determined by this tool [9] FTIR is used to synthesize by the solid state method. The stretching of M-O ions in the spinel ferrites was accepted by different peaks. The absorption peak at 350 - 450 cm⁻¹ shows O₂ (Oxygen) and the absorption peak at 550 - 850 cm⁻¹ in the octahedral regions of oxide ions in the metal reflect O₂ (Oxygen) and Metalide tensile vibrations. These two peaks confirm the characteristic peaks of all spinel ferrites and the formation of the metal-oxygen band in spinel ferrites. As shown in Figure 2.

This shape show that FTIR spectra at area hotness are sintered at 800˚C with dissimilar x values of the Co_1−xCe_xFe₂O₄ work (x = 0.00, 0.33, 0.66, 1.00) and 400 - 4000 cm⁻¹ wave figure spinel ferrites. Banding peak increase the feelings of metals as well as oxides in octahedral regions. The peaks at 1531.99 and 2372.08 show H-OH and N-O vibration vibrations, respectively. Since the FTIR range is 500 - 4000 cm⁻¹, no alternation stresses of metal and oxide ions in the octahedral regions are observed. The spectra were quite similar for all x (0.001, 0.33, 0.66, 1.00) compound and the marks show good conformity with the creative writing

Table 1

List of band gaps for different materials

Material	Band gap (eV)
(x = 0.00) (Co1.0Fe2O4)	1.4575
(x = 0.33) (Co0.67Ce0.33Fe2O4)	1.3609
(x = 0.66) (Co0.34Ce0.66Fe2O4)	1.4375
(x = 1.00) (Ce1.0Fe2O4)	1.425

[10] . These value of the power steady in the octahedral area are calculated using the following relative.

K = 4 π 2 ν 2 C 2 m

where, ν (wave number), C (speed of light) and m mass of Fe³⁺ - O²⁻ ions (2.061 × 10⁻²³ g), respectively. The change in Fe³⁺ - O²⁻ inter nuclear lengths alter the band positions at A and B sites [11] [12] .

If Μ 2.60 × 10⁻²³ g and the force stable in tetrahedral or octahedral region among μ metal oxide ions is c = 2.99 × 10⁸ cm/s and the grouping band in octahedral regions value.

Ions inside the octahedral region for all compound of the spinel ferrites Co_1−xCe_xFe₂O₄ (x = 0.00, 0.33, 0.66, 1.00). The register in the on top of Table 2 shows the incidence of the combination bands and strength constants in the tetrahedral region for all compound of Co_1−xCe_xFe₂O₄ (x = 0.00, 0.33, 0.66, 1.00) spinel ferrites. The strength modify depends on the occurrence of the combination band. The little shift in the combination band is the verification of the payment of the Ce ions or the alter in the ionic radius and the replacement of the metal oxide ions in the tetrahedral regions.

2.4. SEM (Scanning Electron Microscopy)

The disguise morphology of spinel ferrites of Co_1−xCe_xFe₂O₄ (x = 0.00, 0.33, 0.66, 1.00) was sintered at 800˚C with a SEM scanning electron microscope, ie, estimated for dissimilar composition of x = 0.00, 0.33, 0.66, 1.00. The surface morphological characterization of Co_1−xCe_xFe₂O₄ spinel ferrites synthesized by the

Table 2

List of composition of different materials

Composition	V1 (cm−1)	Stretching Force Constant (Ko × 105 dyne/cm)
0.00	660.44	4.01
0.33	658.74	3.99
0.66	657.08	3.97
1.00	657.08	3.97

solid-state reaction method was performed using Scanning Electron Microscopy (SEM). The SEM analysis provided insights into the surface structure, texture, and grain size of the synthesized ferrites. The SEM images revealed the morphology of the spinel ferrite samples at various compositions (x = 0.0, 0.33, 0.66, 1.0). The surfaces appeared to be relatively smooth and exhibited varying degrees of grain agglomeration. The grain sizes of the synthesized cubic spinel ferrites were observed to be in the range of 1.25 µm to 2.65 µm. The SEM analysis allowed for a detailed examination of the surface features, such as the presence of cracks, porosity, and the distribution of grains. The images provided visual evidence of the structural properties and surface characteristics of the synthesized ferrites. Overall, the SEM characterization of Co_1−xCe_xFe₂O₄ spinel ferrites synthesized through the solid-state reaction method contributed to the understanding of their surface morphology and grain size, which are important factors in determining their properties and potential applications in various fields.

The face morphology of every one micrograph shows an all the similar, well-packed and crack-free granule sharing. At the similar time as the x value increase, the grain becomes occasionally cubic. In adding, the SEM micrograph shows that for the x = 0.0 work the outside is less consistent, but with x values of 0.33, 0.66 and 1.00, the substance becomes all the same. As shown in Figures 3(a)-3(d) respectively.

2.5. Experimental

Synthesis of Co_1−xCe_xFe₂O₄ nanoferrites

Ce substituted Co_1−xCe_xFe₂O₄ where (x = 0.0, 0.33, 0.66, 1.0) nanoparticles were being synthesised with solid state reaction method. Nitrates of Copper, Cerium and Iron were employed to prepare Ce doped Co_1−xCe_xFe₂O₄ nanoferrites. The stochiometric ratios of desired salts were dissolved in deionized water. Sodium hydro oxide (NaOH) mixed in water was added in solutions and were stirred at 80 ^ͦC to keep pH 11. At temperature 80 ^ͦC the attained solution was positioned in water bath for 24 hrs, pursued by filtration. The particles were cleaned through deionized water and followed by ethanol until the pH was 7. Obtained crystals were dried in oven and grinded to acquire fine powder. The achieved powder of each sample was sintered at 800˚C for 8 hrs. Figure 3 shows the whole synthesized process.

3. Conclusion

Co_1−xCe_xFe₂O₄ (x = 0.0, 0.33, 0.66, 1.0) ferrites have been prepared using sol-gel technique. The lattice constants were to be found using SEM analysis and it shows the formation of cubic spinel ferrites. The sintering temperature is about 800oC we get multi-ferrites. The FTIR analysis shows the stretching of bonds on tetrahedral and octahedral sites. The UV-VIS analysis shows the energy band gap.

Conflicts of Interest

The authors declare no conflicts of interest regarding the publication of this paper.

References

1. Coey, J. (2009) Magnetism and Magnetic Materials. Cambridge University Press, Cambridge.

2. Anu, K. and Hemalatha, J. (2019) Magnetic and Electrical Conductivity Studies of Zinc Doped Cobalt Ferrite Nanofluids. Journal of Molecular Liquids, 284, 445-453. https://doi.org/10.1016/j.molliq.2019.04.018

3. Prasad, B.V., Ramesh, K. and Srinivas, A. (2020) Co0.5-xCuxZn0.5Fe2O4 (0≤ x≤ 0.25) Nano Crystalline Ferrites: Structural, Magnetic and Electric Properties. Solid State Sciences, 107, 106325. https://doi.org/10.1016/j.solidstatesciences.2020.106325

4. Néel, L. (1971) Magnetism and Local Molecular Field. Science, 174, 985-992. https://doi.org/10.1126/science.174.4013.985

5. Hasan, M., et al. (2018) Mg and La Co-Doped ZnNi Spinel Ferrites for Low Resistive Applications. Materials Research Express, 6, 016302. https://doi.org/10.1088/2053-1591/aae3f6

6. Kaiser, M. (2010) Influence of V2O5 Ion Addition on the Conductivity and Grain Growth of Ni-Zn-Cu Ferrites. Current Applied Physics, 10, 975-984. https://doi.org/10.1016/j.cap.2009.12.042

7. Ponhan, W. and Maensiri, S. (2009) Fabrication and Magnetic Properties of Electrospun Copper Ferrite (CuFe2O4) Nanofibers. Solid State Sciences, 11, 479-484. https://doi.org/10.1016/j.solidstatesciences.2008.06.019

8. Tsushima K. ,et al. (1971)Jan Smit ed.: Magnetic Properties of Materials, McGraw-Hill Book Co., New York, 1971, 344 pages, 16× 23cm, 7,400 yen JPS 26, 797-798.

9. Iyer, R., Desai, R. and Upadhyay, R. (2009) Low Temperature Synthesis of Nanosized Mn1-xCdxFe2O4 Ferrites. Indian Journal of Pure & Applied Physics, 47, 180-185.

10. Naseri, M.G. and Saion, E.B. (2012) Crystalization in Spinel Ferrite Nanoparticles. Advances in Crystallization Processes, 14, 362-365.

11. Shannon, R.D. (1976) Revised Effective Ionic Radii and Systematic Studies of Interatomic Distances in Halides and Chalcogenides. Acta Crystallographica Section A: Crystal Physics, Diffraction, Theoretical and General Crystallography, 32, 751-767. https://doi.org/10.1107/S0567739476001551

12. Verwey, E. and De Boer, J. (1936) Cation Arrangement in a Few Oxides with Crystal Structures of the Spinel Type. Recueil des Travaux Chimiques des Pays-Bas, 55, 531-540. https://doi.org/10.1002/recl.19360550608