Spinel Nanoferrites Research Articles

Green synthesis of Nd substituted Co-Ni nanospinel ferrites: a structural, magnetic, and antibacterial/anticancer investigation

Co0.5Ni0.5Nd0.02Fe1.98O4 (CoNiNdFO) nanospinel ferrites (NSFs) with and without plant extracts (cardamom seeds, date fruits, flaxseed, tragacanth gum, lavender seeds, and moringa) were prepared using a sol-gel approach. The impact of utilizing different plant extracts on the structural, morphological, and magnetic features of the final products is discussed. Room temperature (300 K) magnetization findings illustrate superparamagnetic (SPM) characteristics for the products synthesized using the cardamom and moringa plant extracts mediated sol-gel approach, whereas the remaining products display ferromagnetic characteristics. On the other hand, lower temperature (10 K) magnetization curves indicate that all the prepared samples exhibit ferromagnetic (FM) behavior. It was found that the magnetic parameters vary greatly with the synthesis approach, plant extract solution, distribution of cations, morphology, and size of NSFs, spin canting, etc. The obtained results indicate that the different synthesis approaches employed in the present investigation are simple, inexpensive, and eco-friendly, and could lead to obtaining interesting magnetic properties. The biological applications of these NSFs were examined. The impact of NSFs with and without cardamom and moringa extracts on human colorectal carcinoma cells (HCT-116) and cervical cancer cells (HeLa) was assessed by checking cell viability using 3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide (MTT) and 4′,6-diamidino-2-phenylindole (DAPI) staining methods. The treatments of NSFs with and without cardamom and moringa extracts decreased cancer cell viability. We calculated the inhibitory concentration (IC50) values for NSFs with and without cardamom and moringa extracts. The treatment of NSFs with and without cardamom and moringa extracts on HCT-116 cells and HeLa cells induced a significant decrease in cancer viability, as revealed by MTT assay. The treatment of NSFs with and without cardamom and moringa extracts caused a noteworthy decrease in colon cancer cells as the number of DAPI stained cells was found to be less in the treated cells. The evaluation of the anti-staphylococcal activity of NSFs with and without cardamom and moringa extracts via the colony-forming unit (CFU) method showed growth inhibition of S. aureus. It was observed that the nanoparticles synthesized via green synthesis had a marked cell count reduction, proving the microbial toxicity of nanoparticles to S. aureus.

Synthesis and characterisation of MxFe3−xO4 (M = Fe, Mn, Zn) spinel nanoferrites through a solvothermal route

Synthesis and characterisation of MxFe3−xO4 (M = Fe, Mn, Zn) spinel nanoferrites through a solvothermal route

Structural, Magnetic, and Mossbauer Parameters' Evaluation of Sonochemically Synthesized Rare Earth Er3+ and Y3+ Ions-Substituted Manganese-Zinc Nanospinel Ferrites.

The effect of Er3+ and Y3+ ion-co-substituted Mn0.5Zn0.5ErxYxFe2–2xO4 (MZErYF) (x ≤ 0.10) spinel nanoferrites (SNFs) prepared by a sonochemical approach was investigated. Surface and phase analyses were carried out using SEM, TEM, and XRD. Hyperfine parameters were determined by fitting room-temperature (RT) Mossbauer spectra. Magnetic field-dependent magnetization data unveiled the superparamagnetic nature at RT and ferrimagnetic nature at 10 K. RT saturation magnetization (MS) and calculated magnetic moments (nB) are 34.84 emu/g and 1.47 μB, respectively, and have indirect proportionalities with increasing ion content. MS and nB data have a similar trend at 10 K including remanent magnetizations (Mr). The measured coercivities (HC) are between 250 and 415 Oe. The calculated squareness ratios are in the range of 0.152–0.321 for NPs and assign the multidomain nature for NPs at 10 K. The extracted effective magnetocrystalline constants (Keff) have an order of 104 erg/g except for Mn0.5Zn0.5Er0.10Y0.10Fe1.80O4 SNFs that has 3.37 × 105 erg/g. This sample exhibits the greatest magnetic hardness with the largest magnitude of HC = 415 Oe and an internal anisotropy field Ha = 1288 Oe among all magnetically soft NPs.

Sol-Gel Synthesis of Dy-Substituted Ni0.4Cu0.2Zn0.4(Fe2-xDyx)O4 Nano Spinel Ferrites and Evaluation of Their Antibacterial, Antifungal, Antibiofilm and Anticancer Potentialities for Biomedical Application.

BackgroundThe constant rise of microbial biofilm formation and drug resistance to existing antimicrobial drugs poses a significant threat to community health around the world because it reduces the efficacy and efficiency of treatments, increasing morbidity, mortality, and health-care expenditures. As a result, there is an urgent need to develop novel antimicrobial agents that inhibit microbial biofilm formation.MethodsThe [Ni0.4Cu0.2Zn0.4](Fe2-xDyx)O4(x≤0.04) (Ni-Cu-Zn) nano spinel ferrites (NSFs) have been synthesized by the sol–gel auto-combustion process and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray (EDX) and transmission electron microscopy (TEM). The antimicrobial, antibiofilm and antiproliferative activities of Ni-Cu-Zn NSFs were also examined.ResultsThe XRD pattern confirms the secondary phase DyFeO3 and Fe2O3 for substituted Dy3+ samples, and the crystallite size ranged from 10 to 19 nm. TEM analysis of NSFs revealed that the particles were cube-shaped and 15nm in size. NSFs exhibited significant antimicrobial, antibiofilm and antiproliferative activity. At concentration of 1 mg/mL, it was found that the NSFs (ie, x=0.0, x=0.01, x=0.02, x=0.03 and x=0.04) inhibit biofilm formation by 27.6, 26.2, 58.5, 33.3 and 25% for methicillin-resistant Staphylococcus aureus (MRSA) and 47.5, 43.5, 48.6, 58.3 and 26.6% for Candida albicans, respectively. SEM images demonstrate that treating MRSA and C. albicans biofilms with NSFs significantly reduces cell adhesion, colonization and destruction of biofilm architecture and extracellular polymeric substances matrices. Additionally, SEM and TEM examination revealed that NSFs extensively damaged the cell walls and membranes of MRSA and C. albicans. Huge ultrastructural alteration such as deformation, disintegration and separation of cell wall and membrane from the cells was observed, indicating significant loss of membrane integrity, which eventually led to cell death. Furthermore, it was observed that NSF inhibited the cancer cell growth and proliferation of HCT-116 in a dose-dependent manner.ConclusionThe current study demonstrated that the synthesized Ni-Cu-Zn NSFs could be used to develop potential antimicrobial surface coatings agents for a varieties of biomedical-related materials and devices in order to prevent the biofilms formation and their colonization. Furthermore, the enhanced antiproliferative properties of manufactured SNFs suggest a wide range of biomedical applications.

Biosynthesis effect of Moringa oleifera leaf extract on structural and magnetic properties of Zn doped Ca-Mg nano-spinel ferrites

Zn x Ca 0.5-x/2 Mg 0.5-x/2 Fe 2 O 4 ( x = 0.0–0.6) nano-spinel ferrite (NSFs) were prepared by ultrasonic irradiation with Moringa oleifera leaf extract (group A) and without Moringa oleifera leaf extract (group B). The synthesis done with Moringa oleifera leaf extract is green synthesis. The structure and morphologies of both group A and B NSFs were investigated by XRD, SEM, TEM, and FT-IR in details. The crystallite sizes of group A and B products were calculated as within the range of 11–17 nm and 16–28 nm, respectively. The magnetic features of different nanoparticles of group A and B NSFs have been investigated at room (T = 300 K) and low (T = 10 K) temperatures by means of a vibrating sample magnetometer (VSM). All samples displayed superparamagnetic (SPM) behavior at room temperature, with no or negligible coercivity and retentivity. Nevertheless, the different samples revealed opened M−H hysteresis loops at a temperature of 10 K, which indicates their ferromagnetic (FM) behavior at very low temperatures. The various magnetic parameters including the saturation magnetization (M s ), remanent magnetization (M r ), squareness ratio (M r /M s ), magneton number ( n B ), coercive field (H c ), etc. were extracted. The Zn x Ca 0.5- x /2 Mg 0.5- x /2 Fe 2 O 4 ( x = 0.0 – 0.6) NSFs prepared using Moringa oleifera extract (Group A samples) displayed lower M s values in comparison to NSFs prepared without using Moringa oleifera extract (Group B samples). Whereas, the coercivity is found to be larger in Group B samples than in Group A samples. These is mainly ascribed to the variations in particles size upon the use of M oringa oleifera extract. Compared to non-substituted Ca 0.5 Mg 0.5 Fe 2 O 4 NSFs, it is noticed that the M s value increases with Zn 2+ ions substitution. The increase of M s value is ascribed to the strengthening of exchange interactions and redistribution of cations (particularly Fe 3+ ions) within the spinel lattice. At T = 10 K, the H c value decreases with the rise of the Zn 2+ content, which is attributed to the larger crystallites/particles that lead to the lower volume fraction of grains boundaries, which in turn conduce to less pinning of domain walls. The SQR values at 10 K for all NSFs of group A and B are between 0.2 and 0.3, which is below the theoretical limit of 0.5, reflecting the NPs consist of multi-magnetic domains. The obtained magnetic properties of group A NSFs are interesting, suggesting that this method could be considered as an alternative and effective green synthesis route with appropriate control of size, morphology, and physical features of magnetic nanoparticles.

Structural, morphological and temperature dependent electrical traits of Co0.9Zn0.1InxFe2-xO4 spinel nano-ferrites

An intensive research has been begun on spinel nano-ferrites owing to their unique and novel size dependent chemical and physical properties. Indium doped cobalt-zinc spinel nano-ferrites, Co0.9Zn0.1InxFe2-xO4 (x = 0.05, 0.1, 0.15, 0.2, 0.25, 0.3), have been fabricated through solution-combustion (SC) method and characterized for structural, morphological and temperature dependent electric and dielectric behavior. XRD affirmed that all spinel nano-ferrites have single phase. The TEM and EDX micrographs have confirmed morphology and composition of the samples, respectively. The crystallite size has decreased from 23.8 nm to 20.2 nm, while the lattice constant has been seen to enhance from 8.385 Å to 8.426 Å with the replacement of Fe3+ ions by In3+ ions. FTIR spectroscopy has been performed to extract the information about the stretching of metal-oxygen bonds as well presence of various functional groups. Moreover, FTIR has confirmed that there is no deviation in the structure of the Co–Zn spinel nano-ferrites with the addition of In3+ ions. Additionally, there is no significant deviation in the peak positions of respective peaks has been observed except, when composition changes from x = 0.05 to x = 0.10 for peak I and peak II. The resistivity has been observed to decrease with the rise in temperature, which has confirmed the semiconductor character of the prepared spinel nano-ferrites. An enhancement in resistivity has been viewed with the rise in In3+ ions, while a normal dispersion curve has been observed for the variation of the dielectric constant as a function of frequency. Spinel nano-ferrites show a decrease in the dielectric constant with the increase in frequency as well as indium ion content. The dielectric loss tangent shows minute values suggest the utility of the present spinel nano-ferrites for microwave frequency applications.

Tunable cationic distribution and structure-related magnetic and optical properties by Cr3+ substitution for Zn2+ in nanocrystalline Ni-Zn ferrites

We report a microwave-combustion synthesis and structure-related physical properties of Ni0.4Zn0.6−xCrxFe2O4 (0.0 ≤ x ≤ 0.6) nanocrystals in a study of effects by substitution among cations with different oxidation states, Cr3+ for Zn2+. High-quality nanocrystals with an average particle size of 26–33 nm and crystallite size ranged in 23–32 nm are revealed by transmission electron microscopy (TEM) and X-ray diffraction (XRD). Structural properties and cationic redistribution are studied by the XRD Rietveld analysis implying different preferences of Zn2+ and Cr3+ ions to occupy the tetrahedral and octahedral sites, respectively. Further characterization for the characteristic IR absorption bands, ionic valence states, chemical compositions and morphology have been performed by employing the Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS) and electron dispersive X-ray spectroscopy (SEM-EDX). XPS analysis indicates partial reduction of Fe3+ to Fe2+ and further confirms the estimated cationic distribution. UV–Vis absorbance measurements indicated a gradual decrease in the optical energy gap which implies the emergence of sub-band-gap energy levels by the Cr substitution. The magnetic properties were investigated by magnetization measurements showing highly soft magnetic behavior. The values and trend of the observed magnetic moment are consistent with the theoretically calculated magnetic moment based on cationic distributions estimated from the XRD and XPS. Ni-Zn-Cr spinel nanoferrites with soft magnetic properties, magnetization up to 106 emu/g and coercivity down to 70 Oe, tunable by cationic redistribution are introduced for high-frequency power applications.

Structural features and dielectric behavior of Al substituted Cu0.7Ni0.3Fe2O4 ferrites

Aluminum doped Cu–Ni based spinel nano-ferrites Cu0.7Ni0.3Fe2-xAlxO4 are synthesized via sol-gel route and characterized by XRD, FTIR, impedance analyzer, EDAX and SEM. Phase analysis reveals a cubic spinel structure having a single phase. SEM images confirms the uniform formation of materials and elemental stoichiometry is confirmed from EDAX spectra. The size of crystals is within the range of 28.38–30.04 nm. The lattice constant decreases from 8.614 to 8.604 Å with the increase of Al3+ concentration. The metal-oxygen oscillations at octahedral and tetrahedral sites are confirmed by FTIR. Dielectric constant, tangent loss and quality factor are investigated using impedance analyzer within frequency range 1 MHz–3 GHz. Dielectric constant is significantly affected with Al3+ substitution and attained 16.1 value at 2.3 GHz for Cu0.7Ni0.3Fe1.7Al0.3O4. Furthermore, Cu0.7Ni0.3Fe1.7Al0.3O4 showed maximum dielectric loss of 0.4 at 2.5 GHz. The quality factor is enhanced up to 1500 with substitution of Al3+ at concentration of x ═ 0.3. Outstanding dielectric properties of nano-particles suggest that they are good candidates for high-frequency devices and super-capacitors.

Spectral, electrical, and dielectric characterization of Ce-doped Co-Mg-Cd spinel nano-ferrites synthesized by the sol-gel auto combustion method

The spinel nano-ferrites with composition Co0.5Mg0.25Cd0.25Fe2-xCexO4 (0.0 ≤ x ≤ 0.2 with a step interval of 0.05) synthesized by sol-gel auto combustion method. Samples sintered at a significant temperature of 800 °C for 8 h. XRD confirmed the formation of spinel matrix and reduction in lattice constant from 8.3941 Å to 8.3598 Å by increasing Ce3+ cations. The crystalline size of prepared nano-ferrites reduced from 33.6 nm to 14.5 nm. Two absorption bands in the range of 405.23–435.12 cm−1 for octahedral and 510.85–523.21 cm−1 for the tetrahedral site were detected by using FTIR. The UV–visible study showed the optical band gaps decreased from 3.01 eV to 2.25 eV with decreasing Ce3+ doping. The electrical resistivity of as-prepared nano-ferrites increased in the Ferro region and decreased in the Para region with increasing temperature. The resistivity decreased with Ce3+ doping increase, and drift mobility has an opposite trend of resistivity. Due to the effect of space-charge polarization, the values of the dielectric constant (ε′) and dielectric constant loss (ε″) and tan δ were reduced as the frequency was increased, and displayed a dispersive behavior at higher frequencies.

Comparison of magnetic and dielectric properties of transition metal nanospinel ferrites, MFe2O4, (M = Co, Cu, Ni, Zn) synthesized by one-pot combustion route

Transition metal spinel ferrites of the formula MFe2O4, (M = Co, Cu, Zn & Ni) were synthesized successfully by very simple one pot solution combustion method through glycine - nitrate route. Characterization was carried using techniques like Powder X ray diffraction (PXRD), Fourier transform Infra-red (FTIR) spectroscopy and Scanning electron microscopy (SEM), which reveals that these ferrites are in the nano crystalline size in the range of 20–60 nm. Also it displays that these spinel ferrites are in single phase and pure form. Vibrating sample magnetometer (VSM) measurements shows that all ferrites are magnetic in nature. CoFe2O4 was found to be a hard magnet whereas NiFe2O4, ZnFe2O4 and CuFe2O4 are soft magnets. To study and compare the dielectric characteristics we used impedance analyzer. Dielectric constant, loss tangent and ac conductivity was measured as a function of increasing frequency and the effect of calcination temperature was also analyzed for all the ferrites. The gradual decrease in dielectric constant and loss tangent with the rise in frequency shows that the ferrites can act as semiconductors. AC conductivity was found increasing with respect to frequency and calcination temperature of the sample. Calcination temperature effect was studied to understand the variation of different conductivity properties which gave an understanding of processing temperature.

Rietveld refined structural, morphological, Raman and magnetic investigations of superparamagnetic Zn–Co nanospinel ferrites prepared by cost-effective co-precipitation route

Rietveld refined structural, morphological, Raman and magnetic investigations of superparamagnetic Zn–Co nanospinel ferrites prepared by cost-effective co-precipitation route

FTIR, Optical, Electrical and Magnetic Properties of Sm3+ Doped Mg Nano Ferrites

Synthesized Sm, doped Mg nano ferrites with composition MgSmxFe2-xO4 (x = 0,0.025, 0.050, 0.075, 0.100) using the technique of citrate-gel auto-combustion method were analyzed through various experimental techniques. XRD analysis confirmed single-phase cubic spinel structure, while FTIR spectroscopic analysis displayed two absorption peaks that are characteristic of spinel nano ferrites. UV-visible spectral analysis was carried out to study the optical absorption behavior of the prepared ferrites. Two probe method was used to study the dc electrical resistivities of Sm doped Mg nanoferrites between 200 °C–500 °C. A plot between log (σT) vs. inverse temperature yields a curve that reveals prepared nano ferrites' semiconducting nature. A study of TEP (Thermo Electric Power) for prepared samples was carried out at a high temperature (573K). Seebeck coefficient and Curie Temperature of Sm doped Mg nanoferrites were observed. Measurements of magnetization were done by using VSM (Vibrating Sample Magnetometer).

Influence of La+3 doped nano spinel ferrites on infrared spectroscopy in elastic properties via O/W micro emulsion method

The elastic moduli of La+3 substituted Ni–Co–Zn nano ferrites synthesized by O/W micro emulsion method have been determined through X-ray diffraction pattern and IR spectral analysis. The analysis of IR spectra indicates the presence of splitting in the absorption band due to the presence of small amounts of Fe2+ ions in the ferrite system. The variation of elastic moduli with composition has been interpreted in terms of binding forces between the atoms of spinal lattice. The elastic moduli values for the compositions are found larger as compared to conventional commercially prepared compositions.

Influence of Calcination Temperature on Microstructure and Properties of (NiCuZn)Fe2O4 Ferrite Prepared via Ultrasonic-Assisted Co-Precipitation

(NiCuZn)Fe2O4 ferrite is a kind of soft magnetic material widely used in multilayer chip inductors because of its high resistivity and excellent magnetic properties at high frequencies. In this study, (Ni0.4Cu0.2Zn0.4)Fe2O4 ferrite powder was prepared by ultrasonic-assisted chemical co-precipitation method, the effect of calcination temperature on the structure and properties of ferrite powders was investigated by modern analytical methods that include differential thermal analysis, X-ray diffraction, transmission electron microscopy, infrared spectroscopy, and vibrating sample magnetometer, respectively. The results show that the grain size increased from 23.5 nm to 38.6 nm and the lattice size increased from 8.384 A to 8.390 A with the increase of calcination temperature from 600°C to 900°C. The TEM shows that the powder particle was uniform and dispersible, and the particle size was about 30nm at 800°C calcination. The saturation magnetization of ferrite powder increases from 45.85emu/g to 50.65emu/g and the coercivity decreases from 65.50Oe to 46.23Oe with the increase of calcination temperature from 700°C to 900°C. The uniform and fine nano-crystalline ferrite particles would reduce the sintering temperature and improve the stability of the properties for spinel ferrite. The preparation of nano-spinel ferrite by ultrasonic-assisted co-precipitation is a worthy wet process for application.

Physical, structural, conductive and magneto-optical properties of rare earths (Yb, Gd) doped Ni–Zn spinel nanoferrites for data and energy storage devices

In this study, an attempt has been made using different concentrations of rare-earth (RE) elements Yb, Gd in Ni–Zn spinel ferrite to examine the magneto-optical and electrical conductivity analysis of the prepared samples. RE doped Ni–Zn ferrite with composition Ni0.5Zn0.5YbxGdxFe2-xO4 (where, x = 0.00, 0.20, 0.40, 0. 60, 0.80 and 1.00) were prepared by one step sol-gel self-ignition approach. XRD and FESEM were used to examine the formation of a single-phase and variations in the grain size with the increasing contents of RE elements in Ni–Zn ferrite NPs. FTIR confirmed the vibrational studies of the RE doped spinel ferrite. The saturation magnetization, remanence, and coercivity elucidated the magnetic nature of the prepared samples. The decreasing trend was observed in the magnetization which may be due to the doping of RE elements at the B sites. UV–Vis spectroscopy verified the semiconducting nature of the synthesized samples which was because of the emergence of optical band gap in the semiconductor region (2.04 eV–2.28 eV). The temperature-dependent electrical conductivity (σDC) was also studied to investigate the conduction mechanism over the 323 K–563 K temperature range. Yb and Gd doped NiZn ferrite is a good candidate for the nanoantennas, quantum information, sensing, isolators, modulators, data storage applications and energy storage devices because of their excellent magneto-optical and electrical properties.

Effect of Al Doping on Magnetic Properties of Co-Mn Nanoferrites Synthesized via Citrate-Gel Method

The structural and magnetic properties of aluminium substituted Co-Mn nanoferrites synthesized via a chemical route viz. citrate-gel autocombustion method have been reported. Aluminium content has been varied from x=0 to x=1 with an increment of 0.2 in Co0.75Mn0.25AlxFe2-xO4. The structural confirmation was done with the basic characterization techniques such as XRD study, FTIR spectroscopic and the surface morphology was examined using SEM and EDX spectroscopic analysis. To study the optical absorption behaviour of the prepared ferrites, UV-visible spectral analysis was carried out. XRD analysis established the formation of cubic spinel structure of the materials with the average crystallite size of 15.5 nm to 19.94 nm. FTIR spectra has shown two absorption peaks that are characteristic of spinel nano ferrites. From the UV-visible spectral data, energy band gap (Eg) values were evaluated. The data witnessed an increase in the Eg value of the ferrite by doping of Al3+ ion into the ferrite. Room temperature magnetization measurements were carried out before and after aluminium doping in the samples using vibrating sample magnetometer. It was revealed that the substitution of aluminium in the lattice has modified the material into a soft magnetic material. Consequently, they find applications in transformer and motor cores.

Traversing the advantageous role of samarium doped spinel nanoferrites for photocatalytic removal of organic pollutants

The present work reportes the pertinence of samarium (Sm) doped spinel nanoferrites as magnetically recoverable photocatalyst for the removal of organic pollutants from wastewater. Thus, a series of Sm substituted spinel nanoferrites, MSmxFe2–xO4 (M = Ni, Co; x = 0, 0.02, 0.06, 0.1) were synthesized via sol–gel methodology. The effect of Sm doping on the structural, morphological, optical and magnetic properties of pristine nanoferrites was investigated systematically. Further, the fabricated samples were explored as photocatalysts for the oxidative degradation of antibiotics (ofloxacin and norfloxacin) and dyes (methyl orange and safranin O). The Sm doped nanoferrites exhibit astonishing catalytic efficacy that can be attributed to higher surface area, octahedral site preference of Sm ions and reduced band gap. The synthesized nanoferrites display excellent recyclability which enables them to be utilized as potential photocatalysts for wastewater treatment.

Influence of Y3+, Yb3+, Gd3+ cations on structural and electromagnetic properties of CuFe2O4 nanoferrites prepared via one step sol-gel method

Rare earths (REs) play a key role in distorting spinel structure by creating some defects at the lattice sites and make them suitable for magnetodielectric applications. In the present study, the nanoferrites of CuRE0.02Fe1.98O4, where REs = Y3+, Yb3+, Gd3+, were prepared using one step sol–gel method. The prepared samples are copper ferrite (CFO), yttrium doped copper ferrite (Y-CFO), ytterbium doped copper ferrite (Yb-CFO) and gadolinium doped copper ferrite (Gd-CFO), respectively. The single-phase structure of all the REs doped nanoferrites was determined by X-ray diffraction (XRD) analysis. The porosity, agglomerations and grain size of the REs doped copper ferrite were examined using field emission scanning electron microscopy (FESEM) analysis. Fourier transform infrared spectroscopy (FTIR) elaborates the phase formation and environmental effects on the REs doped nanoparticles (NPs). The recorded room temperature M−H loops from a vibrating sample magnetometer (VSM) elucidate the magnetic properties of the REs doped spinel nanoferrites. The magnetic saturation (Ms) was calculated in the range of 23.08 to 51.78 emu/g. The calculated coercivity values (272.6 to 705.60 Oe) confirm the soft magnetic behavior of REs doped copper ferrites. Furthermore, the electromagnetic and dielectric properties were assessed using a Vector network analyzer (VNA) from 1 to 6 GHz. The permeability, permittivity, dielectric tangent loss and electric modulus of the REs doped spinel ferrites illustrate that the prepared NPs may be suitable for microwave and high frequency applications.

Impact of Tm3+ and Tb3+ Rare Earth Cations Substitution on the Structure and Magnetic Parameters of Co-Ni Nanospinel Ferrite.

Tm-Tb co-substituted Co-Ni nanospinel ferrites (NSFs) as (Co0.5Ni0.5) [TmxTbxFe2−2x]O4 (x = 0.00–0.05) NSFs were attained via the ultrasound irradiation technique. The phase identification and morphologies of the NSFs were explored using X-rays diffraction (XRD), selected area electron diffraction (SAED), and transmission and scanning electronic microscopes (TEM and SEM). The magnetization measurements against the applied magnetic field (M-H) were made at 300 and 10 K with a vibrating sample magnetometer (VSM). The various prepared nanoparticles revealed a ferrimagnetic character at both 300 and 10 K. The saturation magnetization (Ms), the remanence (Mr), and magneton number () were found to decrease upon the Tb-Tm substitution effect. On the other hand, the coercivity (Hc) was found to diminish with increasing x up to 0.03 and then begins to increase with further rising Tb-Tm content. The Hc values are in the range of 346.7–441.7 Oe at 300 K to 4044.4–5378.7 Oe at 10 K. The variations in magnetic parameters were described based on redistribution of cations, crystallites and/or grains size, canting effects, surface spins effects, super-exchange interaction strength, etc. The observed magnetic results indicated that the synthesized (Co0.5Ni0.5)[TmxTbxFe2−x]O4 NSFs could be considered as promising candidates to be used for room temperature magnetic applications and magnetic recording media.

Changes in the Structure and Properties of Nickel-Zinc Spinel Nanoferrites Series for 3D-Printing

The family of nickel-zinc nanoferrites with general formula NixZn1 – xFe2O4 for 3D printing were synthesized via pyrochemical urea-nitrate method and annealed at temperatures of up to 770 K. The ferrite powder microstructure was studied by SEM and XRD methods. Average nanocrystallite sizes of 21 to 32 nm and average nanoparticles sizes of 22 to 50 nm were determined. The DC electrical conductivity of NixZn1 – xFe2O4 clearly shows the change in conduction behavior of samples with increase in nickel content. The observed low electrical conductivity with values at 0.l-0.3 and 0.8-0.9 parts of nickel ion for NixZn1 – xFe2O4 is due to change in cation distribution in spinel structure. The microwave absorbing properties of ferrites at 9.15 GHz were analyzed by FMR and maximum microwave absorption is that of compositions NixZn1 – xFe2O4 with x = 0.15 – 0.30. Additive manufacturing FDM 3D-printing process with PLA-nanoferrite filament for fabricating magnetic components also was demonstrated.