Decrease In Saturation Magnetization Research Articles

Crystal Chemistry, Magnetic and Dielectric Properties of Nickel Doped Strontium Ferrites

The SrNixFe12−2xO19 (where x = 0.0–0.8) hexaferrites powders were synthesized using Co-precipitation method and the pellets were prepared at 1100 °C/4 h in muffle furnace. XRD, FTIR, SEM and EDS analysis were used to analyze the samples structural parameters. The changes in the lattice parameters ‘a’&‘c’ are due to the differences in ionic radii. The average grain size (<D>) was estimated from SEM images and found to be in between 1.713 m (x = 0) - 0.549 m (x = 1.0). Observations indicated a decrease in saturation magnetization decreased from 68 emu/g (x = 0.0) to 50 emu/g (x = 0.6) and for x > 0.6, MS increases to 64 emu/g (x = 0.8). The coercivity exhibit anisotropic variation with doping concentration. In the present investigation, the samples shows ε = 487; tanδ = 1.97 for x = 0.6, and ε = 181; tanδ = 1.01 for x = 0.8, respectively. The observed results can be explained on the basis of composition,relaxationphenomena and super exchange interaction.

Estimation of iron ion distribution at various sites contributing to saturation magnetization in barium hexaferrite at different sintering temperatures

Barium hexaferrite with generic formula BaFe12O19 was synthesized using sol-gel method by sintering at four different temperatures viz., 950 ∘C, 1050∘C, 1150∘C and 1250∘C. X-ray analysis confirm single phase and from the Rietveld refinement, it has been found that c/a ratio decreases with increase in sintering temperature. An increase in grain size with sintering temperature is evidenced from FESEM morphology. Coercivity declined with increase in sintering temperature and is found to be inversely proportional to grain size. Saturation magnetization of the sintered samples was estimated from hysteresis loops, which show an increase up to 1150∘C and then decrease with further rise in sintering temperature. Decrease of saturation magnetization at 1250∘C is attributed to relocation of Fe3+ ions towards spin down sites. Fe3+ ion distribution contributing to magnetic moment was estimated theoretically using Néel sublattice model with least possible error and was verified using Rietveld refinement analysis.

Mechanochemical Reduction of Synthetic Sulphidic Copper-Bearing Minerals in an Industrial Scale

In this paper the mechanochemical reduction of binary sulphides chalcocite (Cu2S) and covellite (CuS) by elemental iron wereinvestigated. The composition and properties of nano-powders prepared by high-energy milling were analyzed by X-ray diffraction,X-ray photoelectron spectroscopy and magnetic measurements. The XRD results showed that in case of chalcocite Cu2S the reactiontakes place until 360 minutes, as no elemental iron, could be identified afterwards. In case of covellite CuS, after 480 minutes of mechanochemicalreduction, a significant amount of non-reacted elemental iron could still be observed. The investigation of magneticproperties reveals significant decrease of saturation magnetization as a result of milling. XPS results showed a significant surfaceoxidation in both systems. Unlike the conventional high-temperature reduction of chalcocite and covellite, the mechanochemicalreduction is fast and ambient temperature and atmospheric pressure are sufficient for its propagation.

Preparation of fully dense and magnetically controllable CaO-Al2O3-SiO2-Na2O-Fe3O4 glass ceramics by hot pressing

Fully dense and magnetically controllable glass ceramics was successfully synthesized by method of hot pressing using CaO-Al2O3-SiO2-Na2O glass powder and Fe3O4 powder as raw materials. The influences of sintering temperature and time, content and particle size of Fe3O4, as well as particle size of glass powder on the densification and magnetic properties of samples were investigated. It was found that the saturation magnetization gradually increased with increasing magnetite content. In addition, the samples containing smaller size magnetite particles had a higher coercivity. However, for samples using smaller size glass powder, magnetite particles could partially dissolve into the glass matrix, which led to the decrease of saturation magnetization and the increase of coercivity. It was also concluded that the precipitation of crystalline phase from smaller size glass powder caused the decrease of degree of densification, and after decreasing the sintering temperature, the degree of densification of product was enhanced.

Enhanced magnetorheological effect of suspensions based on carbonyl iron particles coated with poly(amidoamine) dendrons

Particle oxidation constitutes a serious ageing phenomenon in magnetorheological suspensions, bringing about deterioration in performance. This study describes commercial carbonyl iron particles that were successfully coated with poly(amidoamine) dendrons and then applied as an oxidation-resistant dispersed phase in magnetorheological suspensions. A synthesis method was adhered to whereby the particles were sequentially treated with ethylenediamine and methyl acrylate, leading to the formation of generation 2 and 2.5 dendrons; these had the capacity for composite particles with a nano-scale dendritic layer to be prepared on their surfaces. Success in applying the coating was confirmed by various techniques, including XPS, TEM, EDX, FTIR and Raman spectroscopy. The controlled approach adopted to coating the carbonyl iron particles resulted in them exhibiting sufficient oxidation stability, with only an ~ 4.5–4.7% decrease in saturation magnetization. Of interest was that their magnetorheological suspensions demonstrated ca 4.8% and 4% higher dynamic yield stress than a suspension based on non-modified particles at the highest intensity of magnetic field investigated, i.e. 438 kA m–1. Notably, sedimentation stability was evaluated by a unique method that involved the use of a tensiometer with a specific testing probe. The aforementioned coating process led to enhanced sedimentation stability of the magnetorheological suspensions based on coated particles possibly due to decrease in the overall density of the particles, enhanced dispersion stability and reduction in the size of their agglomerates in the silicone oil mixtures that were confirmed by optical microscopy. Modification of the particles as proposed has the potential to overcome one of the primary drawbacks of magnetorheological suspensions, this being oxidation instability (which leads to what is referred to as “in-use-thickening”), without negatively affecting their performance in the presence of a magnetic field.

Synthesis, structural and magnetic properties of NiFe2–xLaxO4 (0 ≤ x ≤ 0.10) nanoparticles

Lanthanum substituted nickel ferrites NiFe2–xLaxO4 (0 ≤ x ≤ 0.10) powders have been synthesized for the first time by combustion technique using glycine as a fuel. All the ferrites crystallize in $$ Fd\overset{\_}{3}m $$ space group with cubic symmetry. Very small peaks of both Fe2O3 and LaFeO3 were also detected, the intensity of which increases with increasing La content. No systematic trend in the lattice parameter a with La doping has been noticed. Room temperature magnetization studies, obtained from vibrating sample magnetometer (VSM), exhibit a decrease in saturation magnetization with La doping. Cation distribution, obtained from magnetic measurements, shows that La doped nickel ferrites have inverse spinel structure in which Ni2+ ions predominantly occupy octahedral sites.

Synthesis and characterization of Al3+ substituted Ni–Cu–Zn nano ferrites

Ferro spinels with composition Ni0.2Cu0.2Zn0.6Fe2−xAlxO4 (x = 0.0 to 1.0 in steps of 0.2) were synthesized by co-precipitation method, in oxygen atmosphere, from corresponding analytical grade metal sulfates. Thermogravimetric (TG) analysis shows total mass loss around 30% up to 873 K temperature. X-ray diffraction studies confirm all composition with single-phase spinel, cubic structure with crystallite size 11–21 nm range. With increasing trivalent Al3+ content, lattice parameter ‘a’ decreases. Infrared spectra shown two major absorption bands, the lower frequency band ν2 observed in the range 433–463 cm−1, is assigned to octahedral site and higher frequency band ν1 observed in the range 565–593 cm−1, assigned tetrahedral site. The microstructures of the calcinated samples investigated by scanning electron microscopy and transmission electron microscopy indicate ferrite samples are porous in nature. The magnetic properties such as saturation magnetization and magneton number decrease with increasing Al3+ concentration.

Effect of γ-rays irradiation on structural and magnetic properties of Cd–Mn nanoferrites synthesized via sol-gel auto-combustion method

Manganese-cadmium nanoferrites with the general formula Mn1-xCdxFe2O4 (x = 0.2, 0.5, 0.8) were synthesized via sol-gel combustion method at 1000 °C. Non-magnetic Cd2+ ion was conducted to substitute manganese spinel ferrite (MnFe2O4) nanoparticles. To study the radiation effect on the structural and magnetic properties, some nanoferrite samples were γ-rays irradiated with doses of 25, 50, 100, 200, 400, 700 and 1000 kGy. The obtained FTIR spectra confirmed the formation of a single-phase spinel structure at tetrahedral and octahedral sites. The existence of a single-phase structure in the prepared samples was confirmed by X-ray diffraction (XRD) measurements. The crystallite size was found to be within the range 50–140 nm. The influence of γ-rays irradiation and the Cd2+ and Mn2+ ions substitution on the microstructure, and magnetic properties were investigated for some nanoferrite samples with the general formula Mn1-xCdxFe2O4, (x = 0.2, 0.5 and 0.8). The vibrating sample magnetometer (VSM) was used to study the hysteresis curves of unirradiated and irradiated Mn0.8 Cd0.2Fe2O4 sample at different doses. The obtained results showed that the remnant and saturation magnetization decrease with increasing Cd2+ ion concentration and γ-rays irradiation dose.

Dual-Functional Iron Oxide Nanoparticles Coated with Polyvinyl Alcohol/5-Fluorouracil/Zinc-Aluminium-Layered Double Hydroxide for a Simultaneous Drug and Target Delivery System.

Iron oxide nanoparticles are suitable for biomedical applications owing to their ability to anchor to various active agents and drugs, unique magnetic properties, nontoxicity, and biocompatibility. In this work, the physico-chemical and magnetic properties, as well as the cytotoxicity, of Fe3O4 nanoparticles coated with a polymeric carrier and loaded with a 5-fluorouracil (5-FU) anti-cancer drug are discussed. The synthesized Fe3O4 nanoparticles were coated with polyvinyl alcohol and Zn/Al-layered double hydroxide as the drug host. The XRD, DTA/TG, and FTIR analyzes confirmed the presence of the coating layer on the surface of nanoparticles. The results showed a decrease in saturation magnetization of bare Fe3O4 nanoparticles after coating with the PVA/5FU/Zn/Al-LDH layer. In addition, the presence of the coating prevented the agglomeration of nanoparticles. Furthermore, the pseudo-second-order equation governed the kinetics of drug release. Finally, the coated nanoparticles showed stronger activity against liver cancer cells (HepG2) compared to that of the naked 5-FU drug, and displayed no cytotoxicity towards 3T3 fibroblast cell lines. The results of the present study demonstrate the potential of a nano delivery system for cancer treatment.

Cation ratio and oxygen defects for engineering the magnetic transition of monodisperse nonstoichiometric zinc ferrite nanoparticles

Monodisperse nonstoichiometric zinc ferrite nanoparticles with a tunable size of 4.1–32.2 nm are fabricated via thermal decomposition. An extrinsic impurity phase of the ZnO component is present in the zinc ferrite nanoparticles with a size of <10 nm, but this phase can be eliminated after the air annealing treatment. The atom ratio of Zn/Fe and concentration of oxygen vacancies decrease as the particle size of zinc ferrite increases, causing magnetic transition from superparamagnetism to ferromagnetism. The X-ray magnetic circular dichroism spectra reveal that the spin magnetic moments of Fe3+ are reduced, and the orbital magnetic moments are frozen with the increasing atom ratio of Zn/Fe. Therefore, saturation magnetization decreases. The saturation magnetizations of all the zinc ferrite nanoparticles decrease after the air annealing treatment, suggesting that oxygen vacancies considerably influence the magnetic properties. The air annealing treatment can minimize the number of oxygen defects, which trigger some of the Fe3+-OV-Fe3+ ferrimagnetic couplings to transfer into the Fe3+-O2−-Fe3+ antiferromagnetic couplings. This work provides new insights regarding the magnetic performance of spinel ferrites by tuning the stoichiometric ratio and oxygen defects.

Microwave assisted synthesis of oleic acid modified magnetite nanoparticles for benzene adsorption

Benzene is a carcinogenic, mutagenic and highly toxic nonpolar organic compound, its presence in water occurs as a result of leakage of underground pipes and improper effluent disposal. Adsorption techniques have proven to be efficient for benzene removal from water providing a low maintenance method with high removal efficiencies. Nanoparticles provide high surface areas for adsorption and magnetite particles are specifically advantageous owing to their magnetic characteristics. Magnetite surfaces require modification with hydrophobic compounds for the adsorption of nonpolar pollutants. Herein, magnetite nanoparticles (MNP) were modified with oleic acid to form a magnetite-oleic acid composite (MNP-OA) via microwave synthesis for the adsorption of benzene from simulated wastewater. Infrared analysis confirmed the interaction between magnetite and oleic acid and particle diameters were determined by XRD analysis as 19.7 nm and 17.1 nm for MNP and MNP-OA respectively. Magnetic measurements indicated that both materials were superparamagnetic with a decrease in saturation magnetization after modification due to the non-magnetic layer on the surface. Oleic acid modification improved the benzene uptake of magnetite nanoparticles by approximately 30 % while kinetic studies suggested that a concentration driving force controlled the adsorption process. The adsorbent was regenerated and was efficient for five adsorption-desorption cycles.

Impact of Cr Substitution on Structural, Magnetic, Electric and Impedance Study of Mn-Ni-Zn Ferrites

A series of Cr3+-substituted Mn-Ni–Zn ferrites; Mn0.5Ni0.1Zn0.4Fe2-xCrxO4 (x = 0.0 - 0.4 in a step of 0.1) were prepared by traditional solid-state reaction route. The structural, magnetic, dielectric properties and impedance spectroscopy of these compositions were studied. Phase identification and lattice constant (a0) determination were carried out by X-ray diffraction (XRD). The XRD patterns established the fabrication of a single-phase spinel structure. The FESEM micrographs exposed that the average grain size () increased slightly with chromium (Cr) substitution and then decreased for a higher concentration of chromium in the composition. The real part of initial permeability () diminished owing to the enhanced porosity of the compositions with the increase of Cr3+ content in the composition. The highest relative quality factor (RQF) was attained for the samples with x = 0.1. The magnetic hysteresis was investigated to know the effect of Cr3+ substitution in the composition of the magnetic properties. The decrease of saturation magnetization (Ms) with an enhancement in Cr3+ might be triggered by switching of Fe3+ ions from octahedral to tetrahedral site. The samples with x = 0.1 exhibited the highest anisotropy constant (K). Curie temperatures of the investigated samples were significantly modified to lower temperatures with the Cr3+ content. The frequency characteristics of dielectric properties and impedance spectroscopy had been investigated. The highest dielectric constant (ε') and resistivity were observed for x = 0.1 and x = 0.2 samples. The complex impedance spectra analysis reveals in-depth information about the conduction mechanism, microstructure, and orientation of the grains in the samples.

Influence of annealing temperature on degradation efficiency and iron oxide transformations in CeO2/Fe-oxide sorbents

The microstructural and physical properties of magnetically separable CeO2 (5 wt.%)/Fe-oxide sorbents, applicable for the decomposition of organophosphorus pesticides, are analyzed in dependence on calcination temperature. The sorbents are prepared using a two-step procedure: (1) synthesis of magnetite core from cheap and commercially available raw materials; and (2) the formation of cerium (III) carbonate by precipitation with the ammonium hydrogen carbonate, containing re-dispersed magnetite. The cerous carbonate/magnetite precursor is annealed in a muffle furnace at temperatures ranging from 473 to 1073 K for 2 h to obtain the CeO2/Fe-oxide reactive sorbents. Structural characterization of the samples is performed using X-ray diffraction, scanning electron microscopy, Raman and Fourier transform infrared spectroscopy. Magnetic properties are obtained from hysteresis loops, field-cooled and zero-field-cooled curves, first-order reversal curve (FORC) diagrams, and Henkel plots. Sorbents exhibit an increase in coercivity from 0.2 kA/m to about 20 kA/m and a decrease in saturation magnetization from roughly 50 Am2/kg to 1 Am2/kg after annealing at 973 K. This deterioration of magnetic properties is caused by the transformation of magnetite and maghemite into weakly ferromagnetic hematite, with a typical peak in FORC diagram and a Morin transition at about 200 K. The degradation efficiency towards parathion and paraoxon methyl is about 30% for samples annealed from 473 K to 773 K.

Microstructure, magnetic properties of Ho3+ substituted Ni-Cu-Zn spinel ferrites and application for one pot synthesis of dihydropyrimidinones

Nanoparticles of Ni-Cu-Zn spinel ferrites with Ho3+ substitution were synthesized through the sol–gel auto combustion route. It is illustrated from thermogravimetric analysisand differential thermal analysiscurve that the decomposition of precursors takes place in the temperature range 350–460 oC. The Energy dispersive spectroscopy confirmed the mixing of the Fe, Ni, Cu, Zn, Ho and oxygen elements in stoichiometry proportion in pure and substituted spinel ferrites with desired stoichiometry. X-ray diffraction pattern confirmed the formation of cubic spinel structure without any impurity phases. Lattice constant, X-ray density increases while average crystallite size decreases with increased Ho3+substitution in Ni-Cu-Zn ferrites. The two strong IR absorption bands observed in the range 565–568 (ν1) and 409–438 (v2) cm−1. The obtained crystallite size lies between of 18 – 26 nm, confirmed from transmission electron microscopy. The microstructures of the calcinated spinel ferrites were evaluated by SEM and TEM. It is observed that the increase in concentration of Ho3+ ions saturation magnetization decreases. Prepared Ho3+ substituted Ni-Cu-Zn spinel ferrites were used as catalyst to synthesize the 3,4-dihydropyrimidin-2(1H)-ones.[copyright information to be updated in production process]

Effects of Scandium Doping on Structural and Magnetic Properties of Cobalt Ferrite Thin Films

Structural and magnetic properties of Sc-substituted cobalt ferrites were studied by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and vibrating-sample magnetometry. The ScSUBx/SUBCoFeSUB2-x/SUBO₄ (x ≤ 0.3) specimens prepared as thin films by a sol-gel deposition method were polycrystalline having cubic spinel structure with a small increase in the lattice constant compared to CoFe₂O₄. The Raman spectral analyses suggested that the Sc-doped specimens have higher tetrahedral CoSUP2+/SUP population than that of pristine CoFe₂O₄. The magnetic hysteresis curves of the ScSUBx/SUBCoFeSUB2-x/SUBO₄ specimens indicated that the saturation and remanent magnetization decrease proportionally with the increase of Sc composition (x). The decrease in the ferrimagnetic parameters is understandable in terms of the octahedral substitution of non-magnetic ScSUP3+/SUP ions. However, the octahedral ScSUP3+/SUP ions caused an increase of the coercivity.

Impact of nickel substitution on structure, magneto-optical, electrical and acoustical properties of cobalt ferrite nanoparticles

In this study, we have investigated the impact of nickel substituted cobalt ferrite nanocrystals, which were synthesized by a facile co-precipitation technique. The various physical properties such as structural, electrical, magneto-optical and thermal were studied. These properties were characterized using XRD (X-ray diffraction), FT-IR (Fourier-transform infrared spectroscopy), VSM (vibrating sample magnetometer), UV-visible (Ultraviolet–visible) spectra, LCR (Inductance capacitance resistance) meter and photoacoustic spectrophotometer, respectively. From XRD analysis, single face cubic structure (Fd3m) was determined. It was found that as the nickel substitution increased, the crystallite size (D) was decreased from 17.4 ± 1.7 nm to 6.7 ± 1.2 nm. Various structural parameters such as oxygen positional parameters, bond length and cation distribution were determined. Using FT-IR technique, various types of interionic bonds and the elastic properties with their distribution of ions in the formation of spinel phase was found between 400 and 600 cm−1 for the as-synthesized nanocrystals. The aspect of morphology was determined using TEM (transmission electron microscopy). Surface analysis for the as-synthesized products was found to increase from about 41.8 ± 0.6 m2/g to around 92.7 ± 2.1 m2/g with the increase in concentration of Ni ions. From UV-visible spectrum, empirical relation was calculated which indicates the nature of nano crystallinity of the as-synthesized sample. The electrical properties of the as-synthesized samples were premeditated by utilizing LCR meter; at a function of frequencies (10 Hz −10 MHz) at room temperature (RT) impedance was analyzed. Impedance study confirmed that the as-synthesized sample with major grain boundary contributes to conduction. The product with x = 0.9 shows a low dielectric loss and high dielectric constant and henceforth it can used in electromagnetic devices with high frequency. The hysteresis loop elucidates a steadily decrease in Bohr magneton and saturation magnetization, which indeed exhibited a non-linear conduct, where else we could observe a significant increase of anisotropy constant. The thermal properties such as diffusivity, conductivity and effusivity were determined using photoacoustic spectrophotometer and it was found that highly substituted nano-sample has high thermal stability when compared to the other concentrations.

Structural, Microstructural, Electrical, and Magnetic Properties of CuFe2-(x+y)EuxScyO4 (where x and y vary from 0 to 0.03) Nanoparticles

In the present work, the CuFe2-(x+y)EuxScyO4 nanoparticles were prepared by solution combustion method for reporting the structural, microstructural, dielectric, and magnetic properties of prepared samples. The XRD (X-ray diffractometer) patterns confirm the spinel cubic structure with space group Fd3m. The average crystallite size was found in the range from 25 to 10 nm for x = y = 0.00, 0.01, 0.02, and 0.03 concentrations. The SEM (scanning electron microscopy) investigations indicate the porous nature and particle agglomeration. The elemental composition of the samples was studied by using energy-dispersive X-ray spectroscopy (EDS). The FTIR (Fourier transform-infrared spectroscopy) investigation shows the two absorption bands around 554.07 cm−1 and 468.98 cm−1 due to stretching vibrations of the Cu⟺O metal-oxygen bond at the A-site and stretching vibrations of Fe⟺O metal-oxygen bond at the B-site, respectively. The real and imaginary parts of dielectric constant, dielectric loss tangent, AC conductivity, and impedance spectroscopy have been recorded by the methods of impedance analyzer from the range 0.1 KHz to 1 MHz. The dielectric constant and dielectric loss show maximum value at smaller frequency region and are decreases with increase in frequency. AC conductivity increases with the increase of frequency. The real and imaginary part of impedance spectra as function of frequency was studied. The Cole-Cole plots drawn from the impedance spectra show one semicircle for each of the samples. The magnetic hysteresis loop reveals the soft ferromagnetic nature. The magnetic parameters such as saturation magnetization, coercivity, and remanence magnetization decrease with the increase of Eu3+ and Sc3+ concentration.

EVOLUTION OF FERRO ELECTRIC AND FERRO MAGNETIC PROPERTIES OF RARE EARTH ALUMINIUM SUBSTITUTED M-TYPE BARIUM HEXA FERRITES AT ROOM TEMPERATURE

The ferro-electric and ferro-magnetic properties of rare earth aluminium substituted Mtype barium hexa-ferrites with the composition of BaAlxFe(12-x)O19 where (x=0.2, 0.4, 0.6, 0.8, 1.0 and 1.2) have been prepared by oxides as precursors employing powder metallurgy route. The structural properties, functional groups, 3-D visualization, elemental analysis, surface morphology, magnetic, optical properties and ferro electric properties of the prepared samples have been characterized through X-Ray Diffractometer (XRD), Fourier Transform Infrared Spectroscopy (FTIR), diamond visualization software, Energy Dispersive Spectroscopy (EDS), Scanning Electron Microscopy (SEM), Vibrating Sample Magnetometer (VSM), UV-Visible spectroscopy (UV-VIS) and ZT-IA measurement system respectively. The structural measurements depict the confirmation of M-type barium hexa-ferrite structure. EDS spectrum illustrate the elemental composition of the prepared materials for every corresponding ‘x’ values. The surface morphology shows the existence of platelet like intergranular pores. Magnetic measurements shows that the saturation magnetization (Ms) decreases and coercivity (Hc) increases with increasing aluminium contents. The optical band gap energy increases as the crystallite size decreases. The variation of electric polarization has also been occurred due to the shifting of iron ions in the unit cell structure of oxygen octahedron FeO6.

Effect of chromium ions on the structural, magnetic, and optical properties of manganese–zinc ferrite nanoparticles

The present work describes the synthesis of Mn0.5Zn0.5CrxFe2−xO4 (x = 0.1, 0.2, 0.3) ferrite nanoparticles by solution combustion method and their detailed structural, electrical, magnetic, and optical characterizations. X-ray pattern represents the creation of a single spinel structure. In addition to this, the distribution of cations is also approximated from X-ray study which is then authenticated by the magnetization technique also. The crystalline size (23–21 nm) and lattice parameter (8.39–8.30 A) are found to shrink with the rise in chromium ions. A decrease in saturation magnetization (0.80–0.64 emu/g) and remanent magnetization (0.05–0.03 emu/g) is found with the rise in chromium ions, while the coercivity is found to increase (83–123 Oe) through the adding of chromium ions. FTIR predicted the two absorption bands (ν1 and ν2) near 600 and 400 cm−1. Dielectric constant and loss tangent were observed to decrease with an increase in frequency, whereas AC conductivity attains a nearly constant value at a lower frequency and observed to increase at higher frequencies with the addition of dopant.

Room-temperature ferromagnetism in Gd and Sn co-doped bismuth ferrite nanoparticles and co-doped BiFeO3/MXene (Ti3C2) nanohybrids for spintronics applications

Room-temperature ferromagnetic materials are required for new flourishing spintronic technology. Synthesis of co-doped (Gd, Sn) BiFeO3 (Bi1-xGdxFe1-ySnyO3, x = 0, 0.1, 0.15, 0.25; y = 0.1) nanoparticles and nanohybrid co-doped BiFeO3/MXene system as well as structural morphological, electronic and ferromagnetic properties are analysed. XRD patterns showed distorted rhombohedral structure of pure BFO which undergoes transition of phase from rhombohedral to orthorhombic structure due to the Gd substitution in BFO. From SEM, clear voids and porous network can be observed and agglomeration of particles can be due to the addition of Gd substitutions to the BFO. The hysteresis behaviour was revealed for different concentrations of magnetically active Gd added in BFO host, increments in the concentration of Gd resulted in enhanced saturation magnetizations for different samples mainly due to the alteration in antiferromagnetic ordering at the particle's surface, phase transition due to the Gd substitution, collapse of space modulated spin, suppression of oxygen vacancies and increase in number of Fe ions. The magnetization of the hybrid system shows a clear hysteresis behaviour but with decreased saturation magnetization which is attributed to the super exchange effect at the BGFSO and Ti3C2 interface. Unlike the other reports on magnetism in 2D materials, the present work presents magnetic effect in MXene hybrid system which opens up new material designs for 2D spintronics.