Spinel Nanoferrites Research Articles

Investigation and estimation of structural and dielectric properties of chromium-doped cobalt ferrites nano particles

Abstract Nano ferrite materials are of critical importance in meeting the global demand for microwave and electronic devices, as spinel ferrites possess remarkable morphological, structural, and dielectric characteristics. This study investigates chromium-doped ferrite nanoparticles with the chemical composition CoCrxFe2-xO4 (x = 0.00, 0.30, 0.60, and 0.90), synthesize using the sol–gel technique and subjected to annealing at 900 °C. Energy Dispersive x-ray Analysis EDAX patterns confirmed compositional stoichiometry. X- Ray Diffraction analysis reveals that all samples exhibit a cubic crystal structure. Replacing some of the ions with chromium (Cr3+) led to a decrease in the x-ray density form (5.329–5.324). The average crystallite size in the fabricated samples ranged from 46.07 to 31.84 nm, and the lattice parameters decrease from 8.382 to 8.364 Å as the chromium content increase. Infrared spectra show that lower frequency band (ν2) at around 479.69-392 .60 cm–1 and a higher frequency band (ν1) within a range from 611.05–57661 cm–1 a clear indication of spinel structure characteristics. The examination using FE-SEM indicates that the produced materials exhibit porosity and amorphous characteristics. The significant tangent loss observe at lower frequencies suggests that these materials may have potential applications in medium-frequency devices. Consequently, spinel nanoferrites can offer advantages for advanced electronic and microwave technologies.

Fabrication of Nd-Ho Cosubstituted Co0.5Ni0.5Fe2O4 Nanospinel Ferrites and Exploration of Their Microstructure, Magnetic, and Electromagnetic Characteristics.

The composition and hyperfine structures of Nd3+-Ho3+ ions cosubstituted CoNi nanospinel ferrites (Co0.5Ni0.5NdxHoxFe2-2xO4 (x ≤ 0.05) NSFs) as well as their magnetic and electrodynamic behavior have been presented. The compound Nd-Ho → CoNiFe2O4 (x ≤ 0.05) NSFs were produced using the sol-gel method. XRD powder patterns indicated phase- and substituent-induced modifications of crystallites. The SEM analysis indicated the homogeneous distribution of grains with Nd-Ho cosubstitution. It was found that the values of x had an impact on the hyperfine magnetic field of the A and B sites. The cation distribution was determined by using Mössbauer spectroscopy. The M-H loops' investigations showed that the current NSFs behave ferrimagnetically at both room and low temperatures. An almost continuous rise in the strength of the coercive field was noticed with a rise in Ho-Nd content. The value of calculated squareness ratio values was above 0.5 at both temperatures, entailing that the studied NSFs' structure is made of single magnetic domains. The electromagnetic characteristics of the samples can be explained by the main contribution to electromagnetic absorption being the electric energy losses. Electromagnetic absorbed materials can be applied to provide electromagnetic compatibility and develop functional electromagnetic shields.

Solar light-mediated photocatalytic degradation of noxious organic dyes by Co2+ and Y3+ co-doped Ni0.6Mg0.4Fe2O4 spinel nanoferrites

Spinel ferrites are promising magnetic ceramic materials that are gaining attention as heterogeneous photocatalysts because of their relatively narrow band gap, which aids in renewable solar energy harvesting, and their incredible magnetic properties, which enable their reusability. In this paper, Co2+ and Y3+ co-doped Ni0.6Mg0.4Fe2O4 spinel nanoferrites were synthesized via the sol-gel auto-combustion route. Co2+ and Y3+ doping instigated a narrowing of the band gap, upgrading the visible light absorption characteristics of Ni-Mg ferrite. The peaks of X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectra affirm the formation of a cubic spinel structure. The field emission scanning electron microscopy (FESEM) images expose the agglomerating nature and energy dispersive X-ray analysis (EDX) reveals the elemental composition of the fabricated Co2+ and Y3+ co-doped Ni-Mg ferrite. The hysteresis loops obtained from vibrating sample magnetometry (VSM) measurements elucidate the ferrimagnetic nature of the ferrites, which is significant for efficient magnetic recovery and the reusability of the photocatalysts. The Brunauer-Emmett-Teller (BET) experiment implies the enlargement of the surface area of Ni-Mg spinel ferrite with Co2+ and Y3+ co-doping. The photoluminescence (PL) spectra explain the effective charge carrier separation in the co-doped ferrites. The inclusion of Co2+ and Y3+ ions into the spinel lattice of Ni-Mg ferrite has greatly augmented the photocatalytic degradation capability, showing an efficiency of ∼99%. The recyclability studies validate the use of Co2+ and Y3+ co-doped Ni-Mg ferrite in the abatement of water pollution by deteriorating the detrimental organic pollutants.

A comparative study of Nd and Sm doping on the structural, magnetic, and electromagnetic traits of Mg-Zn spinel nanoferrites

A comparative study of Nd and Sm doping on the structural, magnetic, and electromagnetic traits of Mg-Zn spinel nanoferrites

Characterization of Co-doped Ni-Mn spinel nanoferrites: A Multi-faceted evaluation of structural, optical, elastic, and magnetic properties

This study presents the synthesis and comprehensive evaluation of nanocrystalline CoxNi0.5-xMn0.5Fe2O4 (0.0 ≤ x ≤ 0.5) ferrites. Utilizing a variety of analytical techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible (UV–Vis) spectroscopy, field emission scanning electron microscopy (FESEM), and vibrating sample magnetometry (VSM), we characterized the structural, optical, elastic, and magnetic properties of the synthesized nanoparticles. Our findings reveal that increasing Co content leads to a systematic increase in lattice constant from 8.33 Å to 8.39 Å and influences the crystallite size, which ranges between 10 and 15 nm as determined by XRD. Notably, the band gaps of these nanoparticles span from 2.8 to 3.6 eV, varying with Co concentration. Magnetic measurements indicate a transition from superparamagnetic-like behavior at x = 0 to enhanced saturation magnetization, remanence, and coercivity with higher Co content. The novelty of this research lies in the detailed correlation between Co substitution and the resultant changes in multiple physical properties of NiMn nanoferrite, offering potential applications in various technological fields such as magnetic storage, sensors, and biomedical applications.

Cr–Sc co-substituted nickel-cobalt nanospinel ferrites: An investigation of their structural, magnetic properties and hyperfine interactions

The chromium and scandium co-substituted nickel-cobalt nanospinel ferrites (NSFs) having general formula of Co0.5Ni0.5ScxCrxFe2-2xO4 (CoNiScCr) (x ≤ 0.10) have been fabricated through the sol-gel route and citric acid as fuel and characterized by X-ray diffractometry (XRD), 57Fe Mössbauer spectroscopy, vibrating sample magnetometry (VSM), and finally by scanning and transmission electron microscopy techniques (SEM and TEM, respectively). The crystallite size (Dmax) values of the products were estimated to lay between 31 and 46 nm, which was calculated by the Scherrer formula. It was observed that the doping ions’ concentration did not have a linear impact on the expansion of the lattice constant. SEM and TEM present the cubic shape of CoNiScCr NSFs. All ratios demonstrate highly agglomerated cubic particles with diverse sizes. Both XRD and EDX (Energy Dispersive X-ray Spectroscopy) analyses confirmed the absence of any impurity/phases. Through an analysis of hysteresis loops at 300 (RT = room temperature) and 20 K, along with a probe of temperature-induced alteration in magnetization M, the magnetic properties of CoNiScCr (x ≤ 0.10) NSFs have been thoroughly investigated. Notably, all products exhibited complementary soft and hard magnetic behaviors at RT and 20 K, respectively. At 20 K, the observation of squareness ratio values surpassing 0.5 exhibits a single-domain behavior at this specific temperature. Magnetic parameters, in general, exhibit fluctuations with increasing doping content. Across the entire range of materials studied, a notable trend emerges as the temperature decreases, the magnetization in the zero field cooling curves shows a non-linear decrease, eventually stabilizing in the field cooling branches. The findings suggest that the inclusion of Sc3+/Cr3+ dopants can be utilized to manipulate and achieve desired magnetic properties in Co–Ni ferrites. The spectra of Mössbauer analysis, which was utilized to establish the distribution of cations, presented four magnetic sextets for all samples. Doped ions are substituted with Fe3+ ions at the B site.

Enhancing the magnetization, dielectric parameters and elastic parameters while simultaneously minimizing coercivity and dielectric loss in nickel-manganese-cobalt ferrite nanoparticles through Ce3+ doping assistance

This study focuses on examining how the rare-earth cerium incorporation affects the magnetic, dielectric, and mechanical characteristics of Ni0.5Mn0.25Co0.25CexFe2-xO4 spinel ferrite nanoparticles. (NMCCF). The nanoferrite Ni0.5Mn0.25Co0.25Ce0.04Fe1.96O4 acquires the lowest coercivity of 567 Oe and the highest saturation magnetization of 52.23 emu/g. All the NMCCFx nanoferrites exhibit a microwave frequency range of 9.47–11.55 GHz, suggesting potential applications in longitudinal recording media and microwave absorbance. Moreover, the nanoferrite Ni0.5Mn0.25Co0.25Ce0.1Fe1.9O4 demonstrates the highest dielectric value of 1871, with an enhancing ratio of 754 %, excellent conductivity at 3.12 μ(Ω.m)−1 along with a remarkably enhanced percentage of 369 %. Additionally, it shows a loss factor of 2.17, with a notable improvement percentage of 26 % compared to the pure NMCCF0 sample at 50 Hz and room temperature. The elastic moduli (longitudinal, shear, Young, and bulk) of the Ni0.5Mn0.25Co0.25Ce0.1Fe1.9O4 nanoferrite increased from 1.21 to 2.77 GPa, 0.25–0.76 GPa, 0.68–1.99 GPa, and 0.87–1.75 GPa, respectively. This study introduces a novel approach to Ni–Mn–Co–Ce spinel nanoferrites, highlighting their magnetic, electrical, and mechanical characteristics, which hold promise for electronic and high-frequency device applications.

Cr-substituted Mn–Zn ferrite nanoparticles: A study of optical, photocatalytic degradation, and radiation shielding evolution

In this work, we investigate the impact of chromium (Cr) additives on the optical, photocatalytic degradation and the radiation attenuation features of chromium-manganese (Mn)-zinc (Zn)-based spinel nanoferrite (named MZCF-nanoferrites. The Kubelka-Munk approach of reflectance results and Tauc's plots were exploited to verify the energy gap (Eg) of the MZCFx ferrite nanoparticles. The nanoferrites MZCF0, MZCF1, MZCF2, MZCF3, MZCF4, and MZCF5 have Eg values 1.826, 1.811, 1.797, 1.784, 1.772, and 1.769 eV, respectively. The comparative study of the photocatalytic degradation for the optimal (Mn0.8Zn0.2Cr0.1Fe1.9O4) nanoferrite sample and many reported photocatalytic materials evidenced that the MZCF5 nanoferrite has methylene blue dye removal ability higher than those materials (96.38 %, in 60 min). Moreover, this comparative study showed the improved photocatalytic degradation stability performance of the present nanoferrites (just 1.65 % efficiency was decreased after five cycles). The present study proposes a novel approach toward spinel nanoferrites, focusing on the optical and photocatalytic characteristics of the MZCFx-nanoferrites that can be applicable in water treatment fields. Examining linear attenuation coefficient (LAC) of MZCFx-nanoferrite at 0.662 MeV, we observe increased LAC values 0.286 cm−1 to 0.344 cm−1 with increasing Cr additions. Conversely, the half value layer (HVL) values at 0.662 MeV decreased 2.421 cm–2.017 cm with increasing Cr additions. By comparing the HVL values of the MZCFx-nanoferrites at 0.662 MeV to some selected radiation shielding materials, the HVL of the MZCFx-nanoferrites showed smaller values. These findings offer promising perspectives for optimization of spinel nano materials for use in radiation shielding applications.

Impact of Zn addition on structural, morphological, and magnetic properties of thermally annealed Li–Zn nanoferrite

The effect of Zn addition on cationic distribution, structural and magnetic properties of nanocrystalline Li-Zn ferrites are reported. X-ray diffraction confirms the formation of spinel nanoferrites with an average grain diameter of 34 − 82 nm. The addition of Zn results in a linear increase of lattice parameter and X-ray density. Magnetism in the studied samples is governed by the Yafet-Kittel three-sub-lattice model, shown by a non-zero canting angle. The variation in magnetic properties is correlated with the calculated cationic distribution. A new antistructural modeling explains the changes in the concentration of donor and acceptor surface active centers.

Effect of heat treatment on structural, optical and magneto-dielectric properties of Co–Cu spinel nano ferrites

Effect of heat treatment on structural, optical and magneto-dielectric properties of Co–Cu spinel nano ferrites

Rare-earth (Eu3+) substitution impact on the structural, morphological, magneto-dielectric, and electrochemical properties of Cd0.45Co0.55Fe2−y Eu y O4 spinel nanoferrites

A series of Cd0.45Co0.55Fe2−yEuyO4 (y = 0.0, 0.1, 0.2, 0.3) spinel nanoferrites (SNFs) were synthesized using a self-igniting process and employed as electrode materials for supercapacitor applications. The results demonstrated the formation of a single SNFs phase, as shown by the XRD data. The crystallite size lies between the range of 29.30–51.12 nm. The porosity percentage is within the range of 31.37%–32.99%. Rietveld refinement of XRD and Raman analysis revealed the pure spinel phase and no secondary phase was observed. The saturation magnetization and magnetic anisotropy were also decreased with the addition of Eu3+ in Cd–Co SNFs. The high coercive field was enhanced for Eu3+ doping as compared to pure Cd–Co SNFs. The dielectric constant was improved with the substitution of Eu3+ in Cd–Co SNFs. The dielectric tangent loss was reduced with the doping of Eu3+. The electrochemical performance of the Eu3+ doped Cd–Co SNFs achieved an impressive maximum specific capacitance at a lower scan rate. Based on these findings, the outstanding electrochemical performance of the Eu3+ doped Cd–Co SNFs suggests their potential as promising materials for high-frequency, magnetic ferrofluid, and supercapacitor electrodes.

High photocatalytic degradation of methylene blue and enhancing the magnetization, AC conductivity of Dy3+ and Ce3+ doped CdCoFe2O4 nano ferrites

Photocatalysts that combine with dielectric and magnetic properties are vital because of a wide variety of applications for these combinations, and nanostructured magnetic semiconductive materials have attracted significant interest due to their potential applications. A series of Cd0.4Co0.6DyXCeXFe2-2XO4 spinel nano ferrites (nFs) were synthesized by using a highly efficient low-temperature method of citrate sol-gel auto-combustion for Methylene Blue (MB) dye degradation photocatalysts under visible light irradiation that combines with dielectric and magnetic properties are vital because of a wide variety of applications for these combinations, and nanostructured magnetic semiconductive materials have attracted significant interest due to their potential applications. The recycled MB is one of the hazardous textile dyes that is used extensively but causes risks for both humans and the environment. The prepared Dy3+ and Ce3+ doped Cd–Co nFs were polycrystalline with cubic structure, and crystalline size was increased from 15.78 to 21.02 nm with higher crystallinity, and the surface morphology changes from a spherical shape to a hexagonal shape with higher doping concentrations. The direct optical band gap values are increased. FTIR spectra reveal the stretching vibrations along the [M↔O] bond tetrahedral (A) and octahedral (B) sites. HRTEM results revealed that the prepared Cd–Co nFs have higher crystalline nature and high porosity. VSM indicates the sample's soft magnetic action and hysteresis loops showed the highest saturation magnetization (Ms) is 12.243 emu/g, and retentivity increases around 6.038 emu/g, decreasing the dielectric tangent loss, dielectric constant and dielectric loss. The AC conductivity raised with applied frequency. The PL gives a blue emission, and photocatalytic has the highest degradation activity 40.93 % of MB would be successful after 120 min irradiation of X = 0.07 Dy3+ and Ce3+ doped Cd–Co nFs.

Reduced A–B super exchange interaction in zirconium doped cobalt ferrite due to laser irradiation

The impact of Nd:YAG laser irradiation and the addition of zirconium ions (Zr4+) on the physical properties of CoFe2O4 spinel nano-ferrites has been studied. The co-precipitation method was used to synthesize the samples. X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) were employed to examine the structure and morphology. The decrease in the Curie temperature Tc is due to the laser irradiation and the increase in the Zr content of the sample. This decline in Tc is a result of an increase in the canting of the spins, leading to a change in the thermal energy needed for compensate the spin alignment. The difference in the Tc between the non irradiated and the irradiated samples is about 7%, 43% and 34% for CoFe2O4, Co1.1Zr0.1Fe1.8O4, and Co1.3Zr0.3Fe1.4O4, respectively. The decrease in the coercivity of the laser irradiated sample is due to a reduction in the magnetic anisotropy and an altered distribution of the cations (Co2+, Fe3+, Zr4+). The observed trend indicates that laser irradiation, and Zr substitution, can be used to modify the magnetic hardness of the samples. The low coercivity of irradiated Co1.1Zr0.1Fe1.8O4 makes it suitable for a range of applications. The high-frequency response of the Co1+xZrxFe2–2xO4 NPs shows that they can operate within the frequency range of 7.5 GHz–11.56 GHz.

Impact of Cu and La on the structural, morphological, magnetic, photocatalytic, and antibacterial traits of cobalt spinel nanoferrites

Impact of Cu and La on the structural, morphological, magnetic, photocatalytic, and antibacterial traits of cobalt spinel nanoferrites

Ce3+ doped zinc manganese ferrite nanoparticles: Tuned mechanical, dielectric and radiation shielding characteristics

In this paper, the impact of cerium (Ce) additives on the structural, electrical and radiation attenuation characteristics of cerium zinc (Zn)- manganese (Mn)-based spinel nanoferrite, named ZMCeF-nanoferrite was investigated. Our investigation involved a thorough examination of the morphology and distribution of the ZMCeF-nanoferrite utilizing HR-TEM analysis, which revealed showcasing the distinctive spherical morphology of the nanoparticles along with observations of their aggregation tendencies. These findings are ascribed to the heightened magnetic interactions between the ZMCeF-ferrite nanoparticles. The ZMCeF5 nanoferrite demonstrates an optimal dielectric constant value compared to the free Ce ferrite composition, exhibiting an enhancement ratio of 109 %. Additionally, it showcases optimal conductivity, with an upgrading ratio of 780 %, and minimal loss, with an enhancing ratio of 3.5 %. Moreover, the elastic moduli of the ZMCeF5 sample exhibited a marked increase as the Ce content increased. Upon examining the mass attenuation coefficient (MAC) of ZMCeF-nanoferrite across three energy regions, we note a trend of increased MAC values corresponding to higher Ce additions. In contrast, the half-value layer (HVL) values decrease as Ce additions increase. Comparing the HVL values of the current ZMCeF-nanoferrite with those of selected radiation shielding material, we find that HVL of the ZMCeF-nanoferrite exhibits smaller values. These findings present promising prospects for optimizing spinel nanomaterials for use in radiation shielding applications.

Comprehensive analysis of Ni0.4Cu0.2Zn0.4Fe2-4xSn3xO4 nanospinel ferrites: Structural, electrical, and dielectric characterization through advanced techniques

This study extensively investigates Ni0.4Cu0.2Zn0.4Fe2-4xSn3xO4(x ≤ 0.10) nanospinel ferrites, denoted as NCZFe2-4xSn3xO4 NSFs, focusing on their structural, morphological, electrical, and dielectric characteristics. Utilizing various techniques such as SEM, EDX, TEM, XRD, and impedance analysis, the research confirms the cubic spinel structure and composition of the nanoferrites. The substitution of Sn4+ ions into Ni0.4Cu0.2Zn0.4Fe2O4 NSFs is explored, with a thorough examination of dielectric and electrical parameters up to 1.0 MHz and temperatures ranging from 20 to 180 °C. Complex impedance spectroscopy is employed to represent these parameters in a logarithmic 3D graph, revealing insights into ac/dc conductivity, activation energies, dissipation factor, dielectric constant, and loss. The study observes adherence to the power-law frequency rule in ac conductivity and highlights the impact of temperature and substitution ratios on grains, grain boundaries, and elemental composition. The investigation suggests a conduction mechanism involving electron and polaron hopping, and ionic contributions. Dielectric parameters show frequency-dependent changes that relate the dielectric constant to space charge polarization, inhomogeneous dielectric structure, impurities, and grains/grain boundaries. Cole-Cole impedance plots display semicircles dependent on substitution ratios and temperature, emphasizing contributions from grains, grain boundaries, and ionic mobilities. The Nyquist plots of Cole-Cole impedance functions further underscore substantial complexity in the conduction mechanism of the substituted NCZFe2-4xSn3xO4NSFs.

Effect of heavy Dy3+ doping on the magnetic, structural, morphological, and optical characteristics of CuDyxFe2-xO4 nanoparticles

The present study explored the impacts of dysprosium (Dy³⁺) doping on the structure, optical, and magnetic characteristics of CuDyxFe2-xO4 nanospinel ferrites synthesized via a hydrothermal method. X-ray diffraction revealed a tetragonal spinel matrix with increasing Dy³⁺ content, accompanied by a secondary Dy2O3 phase at higher dopant levels for x ≥ 0.1. Crystallite size and microstrain increased with doping, while infrared spectroscopy confirmed the spinel structure and distinct vibrational modes. Interestingly, saturation magnetization displayed a non-monotonic trend, first rising due to spin polarization and cation redistribution, then decreasing with higher Dy³⁺ content attributable to the Dy2O3 phase and larger grains. Coercivity exhibited a maximum at x = 0.2, reflecting the interplay between magnetocrystalline anisotropy, canting angles, and domain wall pinning. These findings highlight the complex interplay between Dy³⁺ doping and the resulting properties, paving the way for tailored CuDyxFe2-xO4 nanospinel ferrites functionalities. . Further research involving advanced techniques and targeted dopant levels holds promise for optimizing properties for diverse technological applications such as magnetic storage, microwave devices, sensors, and hyperthermia treatment.

The effect of Ce doping on the structural, optical, and photocatalytic degradation of Mn–Co nanoferrites

This work demonstrates the preparation of Ni0.5Mn0.25Co0.25CexFe2-xO4 spinel nanoferrites (NMCCF nanoferrites) using the citrate combustion method. This study also investigated the characteristics of their structure, optics, and ability to degrade under light. The lattice strain and crystallite size of each NMCCF nanoferrite were measured by evaluating the XRD results using Williamson-Hall plots. The crystallite size was between 40 and 78 nm. The hopping lengths, bond lengths, surface areas, and densities of all NMCCF nanocrystals were measured and calculated. FTIR analysis showed two strong frequency bands at 571 and 390 cm−1, which are characteristic of spinel ferrites. SEM was used to investigate the particle size, composition, and distribution of the nanoferrites in the NMCCF sample. Scanning electron microscopy (SEM) analysis revealed the presence of spherical NMCCF nanoparticles and their tendency to aggregate. The Kubelka-Munk function and Tauc plots were used to predict the direct allowed Eg value of the NMCCF samples. NMCCF0, NMCCF1, NMCCF2, NMCCF3, NMCCF4, and NMCCF5 exhibited bandgap values of 1.515, 1.545, 1.506, 1.507, 1.499, and 1.473 eV, respectively. The behavior of Eg can be explained based on two criteria: doping impact and particle size. A comparative analysis of the photocatalytic degradation of the ideal sample (Ni0.5Mn0.25Co0.25Ce0.1Fe1.9O4) and other published photocatalytic materials demonstrated that the NMCCF5 nanoferrite exhibited a greater ability to remove methylene blue dye (97.38 %, within 60 min) compared to those materials. In addition, this comparative investigation demonstrated the enhanced stability of photocatalytic degradation capability exhibited by the current nanoferrites (with just a 1.55 % loss in efficiency after five cycles). This paper introduces an innovative method for producing spinel nanoferrites, with a specific focus on their structural, optical, and photocatalytic properties, which can be useful in the field of water treatment.

Effect of Nano Spinel Ferrites Co0.9Cu0.1Fe2O4 on Non-Isothermal Cold Crystallization Behaviours and Kinetics of Its Composites with Polylactic Acid.

Nanoparticles of spinel ferrites with a composition of Co0.9Cu0.1Fe2O4 (AM NPs) were effectively synthesized via a hydrothermal route. The structure of ferrite nanoparticles was characterized with X-ray diffraction, which showed a single cubic spinel phase. Energy-dispersive X-ray (EDX) spectroscopy and field emission-scanning electron microscopy (FE-SEM) were employed to analyse elemental composition and surface morphology, respectively. Moreover, the effects of the Co0.9Cu0.1Fe2O4 on the morphology of [PLA = polylactic acid] nanocomposites were examined through polarized light optical microscopy (POM) and X-ray diffraction (XRD). The thermal behaviours for tested samples were studied through [DSC = differential scanning calorimetry] and [TGA = thermal gravimetric analysis]. A great number of minor PLA spherulites were detected using POM in the presence of the Co0.9Cu0.1Fe2O4 ceramic magnetic nanoparticles (AM), increasing with AM nanoparticle contents. X-ray diffraction (XRD) analysis showed that the presence of nanoparticles led to an increase in the intensity of diffraction peaks. The DSC findings implied that the crystallization behaviours for the efficient PLA as well as its nanocomposites were affected by the addition of AM nanoparticles. They act as efficient nucleating agents because they shift the temperature of crystallization to a lower value. The Avrami models were used to analyse kinetics data. The experimental data were well described using the Avrami method for all samples tested. The addition of AM to the PLA matrix resulted in a decrease in the crystallization half-time t1/2 values, indicating a faster crystallization rate. TGA data showed that the occurrence of AM nanoparticles decreased the thermal stability of PLA.

Influence of Ni2+ ions on structural, spectral and dielectric properties of Sr–Co spinel ferrites synthesized by sol-gel auto-combustion route

Nickel substituted Sr–Co nano spinel ferrites with composition Sr0.5-xNixCo0.5Fe2O4 (0.0, 0.1, 0.2, and 0.3) were prepared with the help of a sol-gel auto combustion route. The prepared materials were sintered at 800 for four and a half hours. Analysis of XRD confirmed that the material is composed of a cubic spinel structure with a single phase, and its space group is Fd-3m. Rietveld refinement of X-ray diffraction data was done for all prepared compositions using FULLPROF software. As the composition under study contains more nickel than lattice constant, crystalline size, X-ray density, and bulk density decrease. The dielectric properties were observed about frequency. The dielectric properties revealed that dielectric loss, dielectric constant, and ac conductivity decrease with increasing the Ni2+ content. The activation energy (ΔE) was calculated from the slope of Arrhenius plots. The ΔE found in the range of 0.580–0.096 eV. The analysis of XPS was carried out to examine the elemental state of annealed samples. The prepared material is suitable for employment in applications involving high frequencies because the Ni-doped Sr–Co ferrites with the greatest Ni2+ concentration have the lowest dielectric loss, dielectric constant, and tangent loss value.