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The separation and recovery of thorium from monazite is critical to the sustainable development of the nuclear industry as well as to environmental safety. Also, the removal of radionuclides from polluted sources is a critical issue in environmental control. Magnetic ferrite nanoparticles (MCMF-NP, Co0.5Mn0.5Fe2O4) were synthesized (4–22 nm in size) and characterized. MCMF-NP was investigated for Th(IV) separation from their aqueous medium under various test conditions of acidity, time, and Th(IV) concentration, in line with the uptake capacity. The amount of thorium adsorbed is improved when pH, time, and initial concentration are increased. The maximum uptake of Th(IV) by MCMF-NP was observed at pH 3.5–4 and a contact time of 180 min. A favorable adsorption mechanism was shown in the pseudo-second-order rate. Isotherm analysis shows an adequate process described by the Langmuir isotherm. MCMF-NP is an adsorbent capable of successful disposal of Th(IV) from waste solutions with a high uptake of 81.3 mg of Th(IV)/g of MCMF-NP. The possibility of re-using the MCMF-NP, adding value to this content as a way of compensating for the disposal costs, was studied and disused. MCMF-NP shows a good separation of thorium(IV) from monazite leach liquor as well as from wastewater samples.

Nanoparticles of Ni0.5Co0.2Zn0.3Fe2O4 were prepared using the sol‐gel combustion route. The nanoparticles were characterised by x‐ray diffraction to confirm single‐phase formation in a cubic spinel structure. Micro‐ and nanostructural analyses were carried out using field emission‐scanning electron microscopy and field emission‐transmission electron microscopy, respectively. A planetary ball milling technique was used to grind the powder into nanoparticles; the average particle size was 64 nm. Energy‐dispersive X‐ray spectroscopy was used to determine the atomic composition of the sample. Radio‐frequency characteristics were recorded for dielectric measurement in a frequency range of 1 Hz to 15 MHz using a broadband dielectric spectrometer. Terahertz (THz) time‐domain spectroscopy was performed to study THz‐optical parameters such as refractive index, dielectric constant, and conductivity at room temperature in a frequency range of 0.3−2.2 THz using an indigenously developed THz time‐domain spectroscopy setup. The magnetic properties of the sample were studied using a SQUID vibrating sample magnetometer under an applied magnetic field of ±10 kOe. An examination of M‐H loops revealed that the saturation magnetization (Ms), remanent magnetization (Mr) and coercivity (Hc) increased with an increase in temperature from 300 to 50 K.

Nanostructured zirconium ferrite with improved surface area of 392 m2/g has been found to show high adsorption affinity for Co2+, Cu2+, and Zn2+. The adsorption was found to be greatly dependent on pH and the maximum adsorption was found at pH 6. The adsorption trends were found to be best fitted with Langmuir adsorption isotherm with regression coefficient (R2) value of 0.999, 0.998, and 0.999 for Co2+, Cu2+, and Zn2+, respectively, at 288 K. The values of Xm and KL were calculated and showed the maximum adsorption capacities towards Cu2+ and minimum adsorption of Co2+ under the optimized pH, contact time, concentration of adsorbate, adsorbent dose, and temperature. The values of thermodynamic parameters ΔH°, ΔS°, and ΔG° were calculated and showed that the adsorption of Co2+, Cu2+, and Zn2+ on ZFNPs takes place through weak van der Waals interaction. Further, the adsorption of Co2+, Cu2+, and Zn2+ on ZFNPs was found to follow the pseudo–second–order kinetics.

Herein, Fe3O4 and Co0.6Fe2.4O4 nanoparticles were prepared by using the coprecipitation method. In order to prove the synthesis of the spinel ferrites and to calculate the structural parameters of ...

Our goal is to investigate the physical, magnetic and dielectric properties of cadmium ferrite nanoparticles. Here we report the synthesis of nanosized cadmium ferrite (CdFe2O4) spinel ferrite by the sol-gel process using citric acid as a complexing agent. We assessed the properties of nano-CdFe2O4 by a variety of analytical and physical techniques. X-ray diffraction and Fourier transform infrared spectroscopy were performed to confirm spinel phase formation. Surface morphology images and compositional features were obtained using electron microscopy and other imaging techniques. Transmission electron microscopy analysis revealed the formation of nanoparticles with an average particle size of 40 nm. The magnetic properties were characterized by a highly sensitive magnetometer system (SQUID VSM) at room temperature revealing that the sintered sample of cadmium ferrite nanoparticles is ferromagnetic. We also studied dielectric behavior of the sintered pellet of the sample. We determined the frequency dependence of the dielectric permittivity, the loss factor and the impedance of the samples in the frequency range from 100 Hz to 20 MHz, at temperatures from 308–428 K at an interval of 40 °C. The dielectric behavior of ferrites is explained by the interface polarization, arising from the heterogeneous nature of its structure. Further research, both in terms of the preparation and characterization of ferrites, is warranted to better understand the nature and application of ferrites.

For high plant growth and efficient production, manufacture of new nano-fertilizers is an important strategy to repair the nutrients shortage. Copper ferrite nanoparticles (CuFe2O4 NPs) were manufa...

Ferrite nanoparticles are interesting materials owing to their unique physical and chemical properties. The metal-doped ferrites have well-defined structures and magnetic response, such as high per...

We report a facile molten salt route to synthesize Ni2+ substituted Mg-Cu-Zn spinel ferrites with their electromagnetic properties. The ferrite nanoparticles (Mg0.25−xNixCu0.25Zn0.5Fe2O4 with x = 0.0–0.25 in step 0.05) synthesized at 800 °C using sodium chloride as a growth inhibitor, revealed an excellent tuning in electromagnetic properties due to addition of Ni. Single-phase formation of spinel ferrite having crystallite size in the range of 45–49 nm was observed by XRD and confirmed by TEM/SAED spot pattern. The obtained dielectric and magnetic properties (high initial permeability = 592, saturation magnetization = 325 emu, coercivity = 36.86 G) of nanostructured spinel ferrite suggest the possibility of utilization of the developed material for MLCI application. The molten salt chemistry, and thereby its effect on structural, morphological and electromagnetic properties of Mg-Cu-Zn ferrites are discussed.

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Magnetic ferrite nanoparticles (MFNs) with high heating efficiency are highly desirable for hyperthermia applications. As conventional MFNs usually show low heating efficiency with a lower specific loss power (SLP), extensive efforts to enhance the SLP of MFNs have been made by varying the particle compositions, sizes, and structures. In this study, we attempted to increase the SLP values by creating core-shell structures of MFNs. Accordingly, first we synthesized three different types of core ferrite nanoparticle of magnetite (mag), cobalt ferrite (cf) and zinc cobalt ferrite (zcf). Secondly, we synthesized eight bi-magnetic core-shell structured MFNs, Fe3O4@CoFe2O4 (mag@cf1, mag@cf2), CoFe2O4@Fe3O4 (cf@mag1, cf@mag2), Fe3O4@ZnCoFe2O4 (mag@zcf1, mag@zcf2), and ZnCoFe2O4@Fe3O4 (zcf@mag1, zcf@mag2), using a modified controlled co-precipitation process. SLP values of the prepared core-shell MFNs were investigated with respect to their compositions and core/shell dimensions while varying the applied magnetic field strength. Hyperthermia properties of the prepared core-shell MFNs were further compared to commercial magnetic nanoparticles under the safe limits of magnetic field parameters (&lt, 5 &times, 109 A/(m&middot, s)). As a result, the highest SLP value (379.2 W/gmetal) was obtained for mag@zcf1, with a magnetic field strength of 50 kA/m and frequency of 97 kHz. On the other hand, the lowest SLP value (1.7 W/gmetal) was obtained for cf@mag1, with a magnetic field strength of 40 kA/m and frequency of 97 kHz. We also found that magnetic properties and thickness of the shell play critical roles in heating efficiency and hyperthermia performance. In conclusion, we successfully enhanced the SLP of MFNs by engineering their compositions and dimensions.

Перспективным направлением применения микро- и наноразмерных магнитных частиц является создание магнитореологических жидкостей (МРЖ) для систем управляемых устройств гидроавтоматики, в которых такие частицы являются компонентом комплексной дисперсной фазы. Наибольшее значение при поиске магнитных материалов для МРЖ имеет высокое значение напряжения сдвига в суспензиях на основе магнитных частиц при приложении магнитногополя, а также низкие значения коэрцитивной силы. Целью работы являлось изучение структуры, морфологии, магнитных свойств нанопорошков твердого раствора Co,Zn-ферритов и оценка их эффективности в магнитных полях по реологическим свойствам МРЖ, изготовленным с их использованием.Методом распылительной сушки с последующим обжигом в инертной матрице синтезирован порошкообразный кобальт-цинковый наноферрит. С использованием методов магнитного анализа, рентгенофазового анализа, просвечивающей электронной микроскопии, ИК-спектроскопии исследованы его структурные и микроструктурные особенности, магнитные свойства.Порошокообразный наноферрит Co0.65Zn0.35Fe2O4, применяющийся в качестве наполнителя комплексной дисперсной фазы магнитореологических жидкостей, имеет следующие значения коэрцитивной силы Hc (10 K) = 10.8 kOe, Hc (300 K) = 0.4 kOe, а также приведенной остаточной намагниченности Mr/Ms (10 K) = 0.75, Mr/Ms(300 K) = 0.24.Предложенная методика синтеза позволяет получать закристаллизованные частицы ферритов с размерами, не превышающими 50 нм, обладающими при этом высоким напряжением сдвига в магнитореологических суспензиях.Разработанметод управления магнитным и свойства микобальт- цинкового ферритака ккомпонентамагнитореологических суспензий путем замещения ионов кобальта в структуре Co,Zn-шпинели немагнитным двухвалентным катионом в данном случае цинком. 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Cupro-spinel (CuFe2O4) nano-particles have been synthesized by sol gel auto combustion method in this work. The sample has been characterized by X-ray diffraction (XRD) pattern and Scanning Electron Microscopy (SEM). Powder X-ray diffraction pattern (XRD) analysis indicates crystalline single phase nature, and cubic structure of copper ferrite with space group Fd3m. The surface morphology of the samples is studied by Scanning electron microscopy (SEM) which indicates the occurrence of cubical growth, with some cracks due to the presence of voids.

In this article, the synthesis of Aluminium doped copper-cobalt ferrite nanoparticles with enhanced antibacterial activity and magnetic properties are reported. The Co1-xCuxFe2-xAlxO4 (00 = x = 08) particles are prepared by varying doping concentration using co-precipitation technique. The structural characterizations confirm the formation of spinel structure. The substitution of aluminium in copper-cobalt ferrite nanoparticles strongly influence the crystal structure, and particle diameter, and also improves the antibacterial characteristics. The anti-bacterial activity is tested on Gram negative (Escherichia coli or E. coli) and a significant enhancement in antibacterial activity is observed with increase in Aluminium doping ratio.

In this work, we analyze artificial heavy-metal solutions with ferrite nanoparticles. Measurements of adsorption effectiveness of different kinds of particles, pure magnetite or magnetite doped with calcium, cobalt, manganese, or nickel ions, were carried out. A dependence of the adsorption efficiency on the composition of the inorganic core has been observed. Ferrites surfaces were modified by phthalic anhydride (PA), succinic anhydride (SA), acetic anhydride (AA), 3-phosphonopropionic acid (3-PPA), or 16-phosphohexadecanoic acid (16-PHDA) to compare the adsorption capability of the heavy metals Cd, Cu and Pb. The obtained nanoparticles were structurally characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Mössbauer spectroscopy. The amounts of Cd, Cu and Pb were measured out by atomic absorption spectroscopy (AAS) and energy dispersive X-ray (EDX) as comparative techniques. The performed study shows that SA linker appears to be the most effective in the adsorption of heavy metals. Moreover, regarding the influence of the composition of the inorganic core on the detection ability, the most effective ferrite Mn0.5Fe2.5O4 was selected for discussion. The highest heavy-metal adsorption capability and universality was observed for SA as a surface modifier.

The mass susceptibility (χmass) and mass magnetization (Mmass) were determined for a series of ternary manganese and zinc ferrite nanoparticles (Mn–Zn ferrite NPs, MnxZn1−xFe2O4) with different Mn:Zn ratios (0.08 ≤ x ≤ 4.67), prepared by the thermal decomposition reaction of the appropriate metal acetylacetonate complexes, and for the binary homologs (MxFe3−xO4, where M = Mn or Zn). Alteration of the Mn:Zn ratio in Mn–Zn ferrite NPs does not significantly affect the particle size. At room temperature and low applied field strength the mass susceptibility increases sharply as the Mn:Zn ratio increases, but above a ratio of 0.4 further increase in the amount of manganese results in the mass susceptibility decreasing slightly, reaching a plateau above Mn:Zn ≈ 2. The compositional dependence of the mass magnetization shows less of a variation at room temperature and high applied fields. The temperature dependence of the mass magnetization of Mn–Zn ferrite NPs is significantly less for Mn-rich compositions making them more suitable for downhole imaging at higher temperatures (>100 °C). For non-shale reservoirs, replacement of nMag by Mn-rich Mn–Zn ferrites will allow for significant signal-to-noise enhancement of 6.5× over NP magnetite.

This work deals with the synthesis, characterization of gadolinium ferrite nanoparticles, and its use as an electrochemical sensor for detection of dopamine. For the synthesis of gadolinium ferrite nanoparticles (GdFeO3 NPs), the combustion technique was employed using gadolinium oxide and ferric nitrate as precursor materials with sugar and ethanolamine as fuel. The size, shape and morphology of nanomaterials were determined by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The crystallite size of synthesized nanoparticles was found to be in the range of 40–45[Formula: see text]nm with a cubic crystal system. The electrochemical sensor, GdFeO3 NPs@graphite paste (GdFeO3/GP), was prepared by using synthesized nanomaterials and graphite powder by mixing in mortar in 1:4 ratio. cyclic voltammetry (CV) and Differential pulse voltammetry (DPV) techniques were employed to assess the electrochemical properties of the developed sensor. The result indicated that the developed sensor possessed better sensing ability, where minimum detection limit of dopamine at GdFeO3/GP electrode was 700[Formula: see text]nM with linearity range from 5[Formula: see text][Formula: see text]M to 160[Formula: see text][Formula: see text]M.

A general and efficient biogenic CuFe2O4 MNP’s catalyzed synthesis of ynones has been reported for the first time. The reaction occurs in solvent free conditions without the use of any harsh conditions. The average diameter of the nanoparticles was found to be 13.07 nm. The advantages of the protocol include heterogeneous catalysis, easy recyclability of the catalyst and short reaction time.

Cu0.5Co0.5Fe2O4 magnetic nanoparticles were prepared, characterized and employed as bench-top, highly active and magnetically separable nanocatalysts for the synthesis of 2-amino-4H-chromene derivatives. A wide range of 2-amino-3-cyano-7-hydroxy-4(phenyl)-4H-chromenes were synthesized with high isolated yields during very short reaction times using Cu0.5Co0.5Fe2O4. Interestingly, the catalyst could be separated using only a simple magnetic decantation and reused six times with no considerable loss of efficiency. The high catalytic activity of Cu0.5Co0.5Fe2O4 nanoparticles was attributed to the presence of both copper and cobalt in its framework, which provide a synergistic catalytic effect with enhanced activity in comparison to single metal-incorporated spinels.

Magnetically separable copper ferrite nps as a catalytic system, under solvent free reaction condition for synthesis of 2-arylquinazolines has been reported. (2-aminoaryl)methanols and various types of oxime ethers were efficiently converted into desired products in moderate to good yields. This protocol offers a greener and atom efficient process, using recyclable heterogeneous catalytic system.

To produce multi-dopant ferrite nanoparticles, the ‘Extended LaMer’ and seed-mediated growth techniques were combined by first utilizing traditional thermal decomposition of metal acetylacetonates to produce seed particles, followed by a continuous injection of metal oleate precursors to increase the volume of the seed particles. With the choice of precursors for the seeding and dripping stage, we successfully synthesized particles with manganese precursor for seeding and cobalt precursor for dripping (Mn0.18Co1.04Fe1.78O4, 17.6 ± 3.3 nm), and particles with cobalt precursors for seeding and manganese precursors for dripping (Mn0.31Co0.74Fe1.95O4, 19.0 ± 1.9 nm). Combining transmission electron microscopy, energy-dispersive x-ray spectroscopy, x-ray diffraction, and vibrating sample magnetometry, we conclude that the seed-mediated drip method is a viable method to produce multi-dopant ferrite nanoparticles, and the size of the particles was mostly determined by the seeding stage, while the magnetic properties were more affected by the dripping stage.

Nitrile butadiene rubber (NBR) samples filled with cobalt–zinc (Co-Zn) ferrite nanoparticles (Co1− xZn xFe2O4, where x = 0, 0.2, 0.4, 0.6, 0.8, 0.9, 0.95 and 1) were prepared. The structure and morphology of Co-Zn ferrite nanoparticles were investigated using X-ray diffraction, transmission electron microscopy, and Fourier transform infrared (FTIR) spectroscopy, while the structure of the Co-Zn nanoferrite-filled NBR composites was studied using scanning electron microscopy and FTIR spectroscopy. The influence of ferrite composition on cure characteristics, mechanical properties and hardness showed an improvement up to x = 0.8. Dielectric parameters showed an enhancement with ferrite composition.

Copper ferrite CuFe2O4 nanoparticles were synthesized by sol-gel method with different annealing temperatures (200, 450, 650 and 850) °C. Structural, morphological, magnetic and electrical properties were studied using X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM) and LCR meter. The XRD patterns showed the system structure in Cu-ferrite had deformed at 650 °C from a cubic to a tetragonal system with apparrent a secondary phase CuO. Lattice constant decreases with increasing annealing temperatures, while crystalline volume increases. The FT-IR spectrum of sample under investigations shows two significant absorption bands, which refer to the formation of a single-phase cubic spinel. Magnetization revealed a soft ferromagnetic behavior for the composition sintered at 850 °C. The saturation magnetization, remnant magnetization, and coercivity were 32 emu.g−1, 11.64 emu.g−1, 517.16 emu.g−1, respectively. The electrical measurement of sample shows decrease in the real and imaginary part of dielectric constant with increasing frequency while and AC conductivity increasing.

Typical copper ferrite nanoparticles (CuFe2O4) were used as a catalyst for one-pot synthesis of β-ketophosphonates via the reaction of alkenes with H-phosphonates under conventional heating conditions. The catalyst was prepared by using the coprecipitation method and was analyzed by physiochemical techniques. By using this catalyst system, several types of useful and new β-ketophosphonate products were obtained in very good to excellent yields under optimized reaction conditions in a novel way. Furthermore, the catalyst is recyclable and reusable from the reaction.

Spinel ferrite nanoparticles represent a class of magnetic nanoparticles (MNPs) with enormous potential in magnetic hyperthermia. In this study, we investigated the magnetic and heating properties of spinel soft NiFe2O4, MnFe2O4, and hard CoFe2O4 MNPs of comparable sizes (12&ndash, 14 nm) synthesized by the polyol method. Similar to the hard ferrite, which predominantly is ferromagnetic at room temperature, the soft ferrite MNPs display a non-negligible coercivity (9&ndash, 11 kA/m) arising from the strong interparticle interactions. The heating capabilities of ferrite MNPs were evaluated in aqueous media at concentrations between 4 and 1 mg/mL under alternating magnetic fields (AMF) amplitude from 5 to 65 kA/m at a constant frequency of 355 kHz. The hyperthermia data revealed that the SAR values deviate from the quadratic dependence on the AMF amplitude in all three cases in disagreement with the Linear Response Theory. Instead, the SAR values display a sigmoidal dependence on the AMF amplitude, with a maximum heating performance measured for the cobalt ferrites (1780 W/gFe+Co), followed by the manganese ferrites (835 W/gFe+Mn), while the nickel ferrites (540 W/gFe+Ni) present the lowest values of SAR. The heating performances of the ferrites are in agreement with their values of coercivity and saturation magnetization.

Simple combustion route was implemented for the preparation of Mo-substituted magnesium ferrite nanoparticles; MgFe2−2xMoxO4 (x = 0.0, 0.1, 0.2 and 0.3). Samples, with x = 0.0, 0.1 and 0.2, revealed only the cubic spinel ferrite phase. Sample with x = 0.3 showed very small amount of FeMoO4, beside MgFe2O4. The lattice parameter diminished with increasing molybdenum contents to x = 0.1, then increased at x ≥ 0.2. The saturation magnetization (Ms) increased from 15.65 to 32.05 emu/g with low level of Mo6+ substitution (x = 0.1), then declined with x > 0.1. This is the first investigation to report Ms of Mg ferrite nanoparticles higher than its bulk value. The change in magnetic properties is correlated with cation distribution between tetrahedral sites (A) and octahedral sites (B). Mo6+ replaced the Fe3+ position in the tetrahedral A-sites for x = 0.1. In samples with x ≥ 0.2, Mo6+ occupied both A-sites and B-sites. Mo substitution decreased the crystallite size and increased the microstrain. Mo substitution in MgFe2O4 enhanced the photocatalytic action compared to bare MgFe2O4. The enhancement was due to the increase in structure defect that inhibits the electrons–holes recombination as well as the increase in surface area.

Manganese substituted nickel–copper–cobalt ferrite nanoparticles having the basic composition [Formula: see text] (x = 0.0, 0.1, 0.2, 0.3 and 0.4) were synthesized by sol–gel auto-combustion method. X-ray diffraction (XRD) was used to estimate phase purity and lattice symmetry. All the prepared samples show the single-phase cubic spinel structure. Fourier transform infrared (FTIR) measurements also confirm the cubic spinel structure of the ferrite that is formed. The preparation of samples show these nearly spherical particles by Transmission electron microscopy (TEM). The magnetic properties of Mn[Formula: see text] ion substituted in nickel–copper–cobalt ferrite were studied by Vibrating sample magnetometer (VSM). The saturation magnetization ([Formula: see text]), remanent magnetization [Formula: see text], coercivity [Formula: see text], magnetic moment [Formula: see text] and anisotropy constant [Formula: see text] first increase and then decrease with the increase of [Formula: see text] ions content. They had better magnetism than pure sample and other substituted samples when the substitution amount of [Formula: see text] ions was [Formula: see text]. At [Formula: see text], the maximum values of remanent magnetization [Formula: see text], saturation magnetization [Formula: see text] and coercivity [Formula: see text] are 25.58 emu/g, 61.95 emu/g and 689.76 Oe, respectively. This indicates that the magnetism of ferrite can improve by substituting with the appropriate amount of manganese. However, due to the excess [Formula: see text] ions instead, ferrite magnetism is weakened. This means that these materials can be used in magnetic data storage and recording media.

Theoretical analysis has been carried out to establish the heat transport phenomenon of six different ferromagnetic MnZnFe2O4-C2H6O2 (manganese zinc ferrite-ethylene glycol), NiZnFe2O4-C2H6O2 (Nickel zinc ferrite-ethylene glycol), Fe2O4-C2H6O2 (magnetite ferrite-ethylene glycol), NiZnFe2O4-H2O (Nickel zinc ferrite-water), MnZnFe2O4-H2O (manganese zinc ferrite-water), and Fe2O4-H2O (magnetite ferrite-water) nanofluids containing manganese zinc ferrite, Nickel zinc ferrite, and magnetite ferrite nanoparticles dispersed in a base fluid of ethylene glycol and water mixture. The performance of convective heat transfer is elevated in boundary layer flow region via nanoparticles. Magnetic dipole in presence of ferrites nanoparticles plays a vital role in controlling the thermal and momentum boundary layers. In perspective of this, the impacts of magnetic dipole on the nano boundary layer, steady, and laminar flow of incompressible ferromagnetic nanofluids are analyzed in the present study. Flow is caused by linear stretching of the surface. Fourier's law of heat conduction is used in the evaluation of heat flux. Impacts of emerging parameters on the magneto-thermomechanical coupling are analyzed numerically. Further, it is evident that Newtonian heating has increasing behavior on the rate of heat transfer in the boundary layer. Comparison with available results for specific cases show an excellent agreement. Scopus

Catalytic application of copper ferrite nanoparticles in benzo[g]chromene-3-carbonitril synthesis via one-pot, three-component reaction has been explored. The product was obtained in a high yield (60-90%) in the varied conditions. The catalyst can be recovered and reused for five consecutive running without significant decrease in catalytic activity.Catalytic application of copper ferrite nanoparticles in benzo[g]chromene-3-carbonitril synthesis via one-pot, three-component reaction has been explored. The product was obtained in a high yield (60-90%) in the varied conditions. The catalyst can be recovered and reused for five consecutive running without significant decrease in catalytic activity.

With the aim of studying the structural and magnetic properties of cobalt doped magnetite nanoparticles (Fe3-xCoxO4), several samples were synthetized by thermal decomposition method using different cobalt concentrations (0 – 5%) at different condition reflux time (30 – 120 min). In this work, we demonstrate that the synthetic parameters highly influence. Both, the morphology and the cobalt concentration, obtaining higher saturation magnetization values for 2 hours reflux. An exhaustive magnetic characterization by means of magnetization and electronic magnetic resonance have established conditions to improve the magnetic response of doped nanoparticles.

The technique of chemical synthesis of metal ferrite nanoparticles in a porous filler structure is developed. It is shown that cobalt ferrite particles located in the pores of carbon weaken the electromagnetic radiation flow passing through a sample of composite material.

A new sustainable strategy for the synthesis of benzoxazoles from substituted N-(2-halophenyl)benzamides was developed in which inexpensive, readily available, air-stable, recyclable copper(II) ferrite serves as a nanocatalyst. The nanocatalyst can be completely recovered with an external magnet and can be used seven times without significant loss of catalytic activity.

A novel, effective and sustainable strategy for the synthesis of aldehydes has been developed using inexpensive, readily available, oxygen-stable and recyclable CuFe2O4 nanoparticles as the catalyst. The corresponding substituted aldehydes were obtained in moderate to good yields by aerobic oxidation of aromatic alcohols in water under dioxygen atmosphere. Importantly, a ligand or a base was not necessary. The catalyst was completely recoverable with an external magnet and could be reused six times without significant loss of catalytic activity.

A novel one pot synthesis of β-hydroxy-1,4-disubstituted-1,2,3-triazoles has been developed by using CuFe2O4 nanoparticles. This protocol involves easily recyclable catalyst in water and avoids the handling of azides as they are generated in situ.

The formation and characterization of multiferroic Gadolinium Ferrite (GdFeO3) nanoparticles has been demonstrated in detail. The structural, magnetic, magnetodielectric, ferroelectric, optical and electrical properties are studied at different temperature ranges. Dielectric properties, DC and AC transport properties and dielectric relaxation behavior are analyzed in electrical characterization. XRD pattern confirms the phase formation where crystallite size, lattice strain, etc. are carried out by Rietveld refinement and Williamson–Hall plot. Average particle size is 64 nm, which is calculated from TEM image. Mixed ferroic order of ferromagnetism and antiferromagnetism along with exchange bias are detected in the nanoparticles. Ferroelectric nature of the sample is confirmed by the P-E hysteresis loops. Positive magnetodielectric coupling is observed in GdFeO3 nanoparticles, which is a signature of multifunctionality nature. Charge transport mechanism of DC and AC applied electric field is successfully analyzed with Mott’s variable range hopping (VRH) and correlated barrier hopping (CBH) theoretical models, respectively. Non-Debye type relaxation behavior is observed with activation energy of 0.37 eV. Optical band gap is calculated from the Tauc plot (2.98 eV) which confirms the semiconducting nature of the sample. Existence of ferromagnetic/antiferromagnetic (FM/AFM) and ferroelectric along with magnetodielctric coupling ensures the multiferroic property of GdFeO3 nanoparticles, which may enhance potentiality in spintronic device applications.

The effect of Li substitution on the structural and magnetic properties of LixCu0.12Mn0.88−2xFe2+xO4 (x = 0.00, 0.10, 0.20, 0.30, 0.40, and 0.44) ferrite nanoparticles prepared by combustion technique has been investigated. Structural and surface morphology have been studied by X-ray diffractometer (XRD) and high-resolution optical microscope, respectively. The observed particle size of various LixCu0.12Mn0.88−2xFe2+xO4 is found to be in the range of 9 nm to 30 nm. XRD result confirms single-phase spinel structure for each composition. The lattice constant increases with increasing Li content. The bulk density shows a decreasing trend with Li substitution. The real part of initial permeability (μi′) and the grain size (D) increase with increasing Li content. It has been observed that the higher the μi′ is, the lower the resonance frequency in LixCu0.12Mn0.88−2xFe2+xO4 ferrites is.