A novel approach for synthesis of M-type hexaferrites nanopowders via the co-precipitation method

M-type hexaferrites; barium hexaferrite BaFe₁₂O₁₉ and strontium hexaferrite SrFe₁₂O₁₉ powders have been successfully prepared via the co-precipitation method using 5 M sodium carbonate solution as alkali. Effects of the molar ratio and the annealing temperature on the crystal structure, crystallite size, microstructure and the magnetic properties of the produced powders were systematically studied. The results indicated that a single phase of barium hexaferrite was obtained at Fe³⁺/Ba²⁺ molar ratio 12 annealed at 800–1,200 °C for 2 h whereas the orthorhombic barium iron oxide BaFe₂O₄ phase was formed as a impurity phase with barium M-type ferrite at Fe³⁺/Ba²⁺ molar ratio 8. On the other hand, a single phase of strontium hexaferrite was produced with the Fe³⁺/Sr²⁺ molar ratio to 12 at the different annealing temperatures from 800 to 1,200 °C for 2 h whereas the orthorhombic strontium iron oxide Sr₄Fe₆O₁₃ phase was formed as a secondary phase with SrFe₁₂O₁₉ phase at Fe³⁺/Sr²⁺ molar ratio of 9.23. The crystallite sizes of the produced nanopowders were increased with increasing the annealing temperature and the molar ratios. The microstructure of the produced single phase M-type ferrites powders displayed as a hexagonal-platelet like structure. A saturation magnetization (53.8 emu/g) was achieved for the pure barium hexaferrite phase formed at low temperature 800 °C for 2 h. On the other hand, a higher saturation magnetization value (M _s = 85.4 emu/g) was obtained for the strontium hexaferrite powders from the precipitated precursors synthesized at Fe³⁺/Sr²⁺ molar ratio 12 and thermally treated at 1,000 °C for 2 h.     

Effect of synthesis conditions on the preparation of BiFeO<Subscript>3</Subscript> nanopowders using two different methods

Bismuth orthoferrite (BiFeO₃) nanoparticles have been synthesized via the co-precipitation and the oxalate precursor methods. Effects of Bi source, annealing temperature, Bi/Fe molar ratio, oxalic acid ratio and Mn²⁺ ion on the crystal structure, crystallite size, microstructure and magnetic properties of the produced powders were systematically studied. The results revealed that bismuth oxychloride and iron oxide were formed using chlorides sources. A single phase of BiFeO₃ was formed from as-made samples with Bi/Fe molar ratio 1.1 using nitrate sources and annealed at 500 and 600 °C for 2 h via the two pathways. The pure BiFeO₃ phase appeared as spherical and pseudocubic-like structure using the co-precipitation and the oxalic acid precursor routes, respectively. A high saturation magnetization (3.94 emu/g) was achieved for powder formed from the oxalate precursor route with Bi/Fe molar ratio 1.0 annealed at 600 °C for 2 h as the result of the formation of Bi₂₅FeO₃₉. Moreover, Mn²⁺ ion addition affected BiFeO₃ properties due to the formation of Bi₂Fe₂Mn₂O₁₀. Hence, the saturation magnetization and the coercive force of BiFeO₃ were improved substantially by substitution of Mn²⁺ ions (BiFe_1-XMn_XO₃, X = 0.1–0.2).     

Water-based sol–gel nanocrystalline barium titanate: controlling the crystal structure and phase transformation by Ba:Ti atomic ratio

Highly stable, water-based barium titanate (BaTiO₃) sols were developed by a low cost and straightforward sol–gel process. Nanocrystalline barium titanate thin films and powders with various Ba:Ti atomic ratios were produced from the aqueous sols. The prepared sols had a narrow particle size distribution in the range 21–23 nm and they were stable over 5 months. X-ray diffraction pattern revealed that powders contained mixture of hexagonal- or perovskite-BaTiO₃ as well as a trace of Ba₂Ti₁₃O₂₂ and Ba₄Ti₂O₂₇ phases, depending on annealing temperature and Ba:Ti atomic ratio. Highly pure barium titanate with cubic perovskite structure achieved with Ba:Ti = 50:50 atomic ratio at the high temperature of 800 °C, whereas pure barium titanate with hexagonal structure obtained for the same atomic ratio at the low temperature of 500 °C. Transmission electron microscope revealed that the crystallite size of both hexagonal- and perovskite-BaTiO₃ phases reduced with increasing the Ba:Ti atomic ratio, being in the range 2–3 nm. Scanning electron microscope analysis revealed that the average grain size of barium titanate thin films decreased with an increase in the Ba:Ti atomic ratio, being in the range 28–35 nm. Moreover, based on atomic force microscope images, BaTiO₃ thin films had a columnar-like morphology with high roughness. One of the highest specific surface area reported in the literature was obtained for annealed powders at 550 °C in the range 257–353 m²g⁻¹.     

Synthesis and Magnetic Properties of Barium Hexaferrite Powders Using Organic Acid Precursor Method

An investigation of the synthesis of BaFe₁₂O₁₉ powders by the organic acid precursor method is reported by acidic and neutral media. X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM) are utilized to study the effect of organic precursor type and annealing temperature on the crystal structure, crystallite size, microstructure and magnetic properties of the formed powders. The XRD analysis showed that the crystalline BaFe₁₂O₁₉ phase was obtained at 1200 °C for 2 h using different carboxylic acids in acidic medium. However, pure BaFe₁₂O₁₉ was achieved at low annealing temperature 1000 °C in neutral medium. SEM micrographs showed that the particles were strongly influenced by type of carboxylic acid and the annealing temperature. VSM study indicated that the saturation magnetization was increased with increasing annealing temperature to 1200 °C as the result of formation of single barium hexaferrites phase. High saturation magnetization (M _s =66.5 emu/g) was achieved for the formed powders in neutral medium using tartaric acid as organic precursor. Wide coercivities of the formed powders (H _c =259–5114 Oe) were obtained.     

Synthesis and Characterization of Nano-crystalline Calcium Hexaferrite Particles by Mechano-Thermal Method

Calcium hexaferrite was synthesized using high-energy planetary ball milling of a mixture of CaCO₃ and Fe₂O₃ powders for 10 hours followed by calcination at 1175 ^°C for 1 h. Effects of Fe₂O₃/CaCO₃ molar ratio, mechanical activation and dopant addition on the phase evolution, morphology, and magnetic properties of the products were studied. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) technique equipped with an energy dispersive spectrometer (EDS), and vibrating sample magnetometer (VSM). XRD results showed that addition of La₂O₃ in the samples lead to the formation of stabilized calcium hexaferrite particles with a mean crystallite size of 54 nm. Moreover, the formation of calcium hexaferrite was acknowledged at Fe₂O₃/CaCO₃ molar ratio of 5. SEM micrographs showed agglomerated particles of calcium hexaferrite with a mean particle size of 1.5 μm. Nano-crystalline Ca_0.8La_0.2Fe₁₂O₁₆ particles show saturation magnetization of 14 emu/g and coercivity of 500 Oe.     

Solvothermal Synthesis of SrFe12O19 Hexaferrites: Without Calcinations

In this study, the effect of temperature on the hydrothermal synthesis of single-phase SrFe₁₂O₁₉ hexaferrite (SrM) was investigated. For this synthesis, annealing or calcination process was applied. The Fe/Ba molar ratio was taken as 8:1. In this study, single-phase SrM NPs were synthesized via hydrothermal method. XRD patterns showed the presence of the hard (SrM) phase in the samples treated at 200 and 220 ^°C. Besides, formation of hexagonal plate-like samples was observed in SEM micrographs. Despite the low magnetization and coercive field values, the presence of the SrM phase was also shown in magnetization measurements. A reduced magnetization was explained by the existence of SrCO₃ and Fe₂O₃ phases, and a high shape anisotropy is probably the reason of low coercivity.     

Preparation of high quality,single domain BaFe12O19 particles by the citrate sol–gel combustion route with an initial Fe/Ba molar ratio of 4

BaFe₁₂O₁₉ particles have been synthesized by citrate sol–gel combustion route in a wide temperature range between 800 and 1200 °C with initial Fe/Ba molar ratios between 12 and 2. Structural, morphological and magnetic properties of the powders have been investigated by XRD, FT-IR, SEM and magnetization measurements. It was observed that both coercivity and specific saturation magnetization increase with annealing at temperatures up to 1100 °C, where a transition from single to multi domain structure occurs. To prevent formation of the hematite phase (α-Fe₂O₃), samples with different Fe/Ba molar ratios between 12 and 2 have been prepared and an intermediate phase, BaFe₂O₄, which may occur in Ba-rich samples has been removed by etching the powders in diluted hydrochloric acid. In this way, it was shown that single domain barium hexaferrite particles having high saturation magnetization, close to the theoretical value, and high coercivity can be synthesized with the initial Fe/Ba molar ratio of 4 in the sol–gel method. The chemical composition of this sample was determined as BaFe_11.80O_19.45 by the EDS analysis and Ba_1.05Fe_11.54O_18.4 using an ICP-MS device. Both are very close to the theoretical formula.     

Optical and electrical properties of Ba1−x Sr x TiO3 nanopowders at different Sr2+ ion content

Barium strontium titanate (BST) Ba_1?x Sr _x TiO₃ nanopowders have been successfully synthesized using oxalate precursor route. The effect of Sr²⁺ ion content from 0.3 to 0.7 on the crystal structure, crystallite size, microstructure, electrical and optical properties was systematically studied. The results revealed that well crystalline single BST phase was formed by annealing the oxalate precursor at 1,000 °C for 2 h. The crystallite size of the BST powders was decreased with increasing the Sr²⁺ ion molar ratios. The crystallite size was decreased from 56.0 to 33.1 nm when the Sr²⁺ ion content increased from 0.3 to 0.7. Additionally, the lattice parameter (a), unit cell volume and X-ray density of BST ware decreased whereas the porosity, % were increased with Sr²⁺ ion concentration. The BST phase appeared as cubic-like structure. The spectrophotometer measurement results demonstrated that the room temperature band gap energy varied with the Sr²⁺ ion composition x. The band gap energy was shifted to low energy and it was decreased from 3.6 to 3.2 eV with increasing the Sr²⁺ ion content from 0.3 to 0.7. Moreover, the DC resistivity was enhanced with increasing the Sr²⁺ ion ratio. The dielectric response obtained for the stressed samples corresponds to a true resonance rather than a dispersion process with a characteristic frequency around 1 GHz at room temperature. However, the peaks commonly observed at GHz frequency were changed with varying the Sr²⁺ ion composition. The high imaginary components of dielectric permittivity for x = 0.3 was found at higher frequency region around 1.6 GHz compared with the samples with x values of 0.5 and 0.7 in which the frequency regions were around 1.25 and 1.15 GHz, respectively.     

Correlation between microstructure and electrical,optical properties of thermal annealed ITO thin films

Indium tin oxide (ITO) thin films with the thickness of 300 nm were deposited on quartz substrates via electron beam evaporation. Five samples were post-annealed in air atmosphere for 10 min at five selected temperature points from 200 to 600 °C, respectively. X-ray diffractometer, Hall measurement system and UV–Vis spectrophotometer were adopted to characterize the ITO thin films. Influence of thermal annealing in air atmosphere on microstructure was investigated. Furthermore, the correlation between microstructure and electrical, optical properties of ITO thin films was discussed in detail. All of the ITO thin films had a polycrystalline structure and a preferred orientation of (222), no matter annealed or not. The intensity ratio of I₍₂₂₂₎/I₍₄₄₀₎ initially increased and then decreased, it reached the maximum of 7.37 after annealed at 400 °C for 10 min. The lattice expansion evidently reduced after annealed at 300 °C or even higher temperature. The variation of mean grain size was minor during thermal annealing process regardless of annealing temperature. The carrier concentration is predominant in electrical conductivity, and it is dependent on the activation of donors and the density of oxygen vacancies. Hall mobility is strongly dependent on the mean grain size, lattice distortion and defect density. The optical transmittance is influenced by the density of oxygen vacancies and the consistency of grain orientations.     

The Influence of Annealing Temperature on the Magnetic Properties of Mn0.5Co0.5Fe2O4 Nanoferrites Synthesized via Mechanical Milling Method

Mn_0.5Co_0.5Fe₂O₄ nanosized ferrites have been made directly from MnFe₂O₄ and CoFe₂O₄ ferrites and from metal oxides by using high-energy ball milling. Single-phase formation and microstructure of the as-milled samples and samples annealed at 100, 200, 300, 400 and 500 ^°C under argon atmosphere were studied using powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). The average grain sizes were estimated from XRD measurements and found to be between 7 and 11 nm. The microstrain for each sample was relieved by annealing due to crystallite growth. Room temperature magnetic properties were investigated by zero-field ⁵⁷Fe Mössbauer spectroscopy and vibrating sample magnetometer (VSM). Saturation magnetizations of the samples were estimated using the empirical law of approach to saturation. The variation of coercive field, saturation magnetization, maximum magnetization and remanent magnetization for each sample was found to depend on the annealing temperature. The coercive fields are observed to increase with increased annealing temperature (from about 300 Oe for the as-milled samples to about 1000 Oe for samples annealed at 500 ^°C) which we attribute to increases in grain sizes.     

The Effect of Variable Binder Content and Sintering Temperature on the Mechanical Properties of WC–Co–VC/Cr3C2 Nanocomposites

WC powders with an average crystallite size of 10 nm were successfully prepared by ball milling of micron-sized tungsten carbide powders. Grain growth inhibitors (VC and Cr₃C₂) with concentrations of 0.6 wt% each were added to nanocomposites of WC–9Co and WC–12Co, in both as-received and milled WC. Powder mixtures were then consolidated using spark plasma sintering technique at 1200 and 1300 °C for 10 min under high vacuum and pressure of 50 MPa. The influence of WC crystallite size, Co content, and sintering temperature over microstructure and mechanical properties of the resulting composites were studied through XRD and FESEM. Densification and attained grain sizes of the sintered products were measured by Archimedes principle and Scherrer procedure, respectively. Moreover, microhardness (H_v30) and fracture toughness were measured and compared for each composition to comparatively assess the individual effect. It was observed that the addition of VC and Cr₃C₂ resulted in decreased densification of the synthesized composites. These grain growth inhibitors were found to limit grain sizes to 131 nm with an average hardness of 1592 H_v30 and fracture toughness of 9.23 Mpam^1/2.     

Magnetic and dielectric properties of polycrystalline La doped barium Z-type hexaferrite for hyper-frequency applications

La³⁺ ion substituted barium Z-type hexaferrite, Ba_3?XLa_XCo₂Fe₂₄O₄₁ powders (X = 0.0, 0.05, 0.10 and 0.15), have been synthesized using sol gel auto-combustion method. The phase identification, microstructure, complex permittivity, complex permeability and static magnetic properties of the samples were studied using X-ray diffraction, scanning electron microscopy, vector network analyzer and vibrating sample magnetometer. The results revealed that introducing La³⁺ ion instead of Ba²⁺ ion led to an obvious enhancement of the electromagnetic properties. The crystallite size of the produced powders was slightly increased with increasing La³⁺ content. The microstructure of the produced powders appeared as hexagonal-platelet like structure. As the La content increase, the static magnetic properties were increased, the real part of complex permittivity was increased while the imaginary part was decreased. Moreover, the real part of complex magnetic permeability was decreased and the imaginary part was increased. The reasons of the obtained results were discussed on basis of electromagnetic theory.     

Annealing Induced Enhancement in Magnetic Properties of Co0.5Zn0.5Fe2O4 Nanoparticles

In this paper, cobalt zinc ferrite (Co_0.5Zn_0.5Fe₂O₄) nanoparticles (NPs) have been prepared using chemical co-precipitation method. In order to investigate the annealing induced effects on their various physical properties, the prepared samples have been annealed at 500 °C, 650 °C and 1000 °C and then compared with as-prepared sample. X-ray diffraction (XRD) patterns of as-prepared and annealed samples at various temperatures exhibit single phase spinel structure. Enhancement in crystallinity and crystallite size is observed with the increase in annealing temperature. The annealing has also greatly influence the morphology and grain size of prepared NPs. The Co_0.5Zn_0.5Fe₂O₄ NPs have shown remarkable enhancement in magnetic moment with increase in annealing temperature. The bandgap energies of Co_0.5Zn_0.5Fe₂O₄ NPs have been measured via UV Spectrometer and observed to decrease with annealing temperature. FTIR spectra of the samples reveal the presence of both high frequency and low-frequency bands due to tetrahedral and octahedral sites, which corroborate well with the XRD results. The observed characteristics of cobalt zinc ferrite NPs as a function of annealing temperature are the rising contender for many data storage and nanodevice applications. Finally, the genotoxicity of prepared nanoferrites has been checked via comet assay.     

Role of annealing temperature on microstructural and electro-optical properties of ITO films produced by sputtering

This study probes the effect of annealing temperature on electrical, optical and microstructural properties of indium tin oxide (ITO) films deposited onto soda lime glass substrates by conventional direct current (DC) magnetron reactive sputtering technique at 100 watt using an ITO ceramic target (In₂O₃:SnO₂, 90:10 wt%) in argon atmosphere at room temperature. The films obtained are exposed to the calcination process at different temperature up to 700 °C. X–ray diffractometer (XRD), ultra violet-visible spectrometer (UV–vis) and atomic force microscopy (AFM) measurements are performed to characterize the samples. Moreover, phase purity, surface morphology, optical and photocatalytic properties of the films are compared with each other. The results obtained show that all the properties depend strongly on the annealing temperature. XRD results indicate that all the samples produced contain the In₂O₃ phase only and exhibit the polycrystalline and cubic bixbite structure with more intensity of diffraction lines with increasing the annealing temperature until 400 °C; in fact the strongest intensity of (222) peak is obtained for the sample annealed at 400 °C, meaning that the sample has the greatest ratio I ₂₂₂/I ₄₀₀ and the maximum grain size (54 nm). As for the AFM results, the sample prepared at 400 °C has the best microstructure with the lower surface roughness. Additionally, the transmittance measurements illustrate that the amplitude of interference oscillation is in the range from 78 (for the film annealed at 400 °C) to 93 % (for the film annealed at 100 °C). The refractive index, packing density, porosity and optical band gap of the ITO thin films are also evaluated from the transmittance spectra. According to the results, the film annealed at 400 °C obtains the better optical properties due to the high refractive index while the film produced at 100 °C exhibits much better photoactivity than the other films as a result of the large optical energy band gap.     

Magnetic properties of nano-clusters lanthanum chromite powders doped with samarium and strontium ions synthesized via a novel combustion method

A novel approach to synthesize a single-phase orthorhombic perovskite lanthanum chromite LaCrO₃ clusters doped with Sm³⁺ and Sr²⁺ ions via gel combustion route was reported. The producing materials were synthesized using metal nitrates as oxidizers and triethanol amine (TEA), N-butyl amine (NBA) or ethylene diamine (EDA) as a fuel. The effect of the annealing temperature, type of organic fuel and the variation of the samarium and/or strontium substitution and its impact on crystal structure, crystallite size, microstructure and magnetic properties of the LaCrO₃ powders formed was systematically studied. The results revealed that a well crystalline single phase of pure LaCrO₃ can be achieved at annealing temperature from 800 to 1000 °C for 2 h. Moreover, each organic carrier materials exhibited a different degree of effectiveness in the synthesis of the mixed oxide powders. The crystal structure was influenced by doped Sm³⁺ and/or Sr²⁺ ions. The crystallite size of the produced powders was increased with the increase the annealing temperature, increasing the Sm³⁺ ion and the decrease of Sr²⁺ ion substitution. The microstructures of the produced powders were found to be nanoclusters octahedra-like shaped. The saturation magnetization of the LaCrO₃ powders increased continuously with an increase in the Sm³⁺ ion concentration and it decreased with an increase in the Sr²⁺ ion up to 0.3 at annealing temperature of 1000 °C for 2 h. The maximum saturation magnetization (0.279 emu/g) was achieved at the Sm³⁺ ion molar ratio 0.3 and annealing temperature 1000 °C. Moreover, wide coercivities can be obtained at different synthesis conditions (49.25 to 522  Oe).     

Effect of annealing time and substrates nature on the physical properties of CuSbS2 thin films

In this study, the annealing time and substrates nature effects on the physical properties of CuSbS₂ thin films were investigated. CuSbS₂ thin films were prepared on various substrates via thermal evaporation technique. The as^_deposited films were annealed in air for 60 and 120 min at 250 °C. The atomic force microscope micrographs of as^_made and annealed thin films show that the surface morphology is affected by annealing time and substrate variation. X^_ray diffraction results show that crystallinity increased with annealing time. The microstructure parameters: crystallite size and dislocation density were calculated. The optical properties were obtained from the analysis of the experimental recorded transmittance and reflectance spectral data over the wavelength range 300–1800 nm. High absorption coefficients (10⁵–10⁶ cm^?1) are reached. Values of E_g are close to the theoretical optimum for efficient conversion of solar radiation into electrical power making the material suitable for photovoltaic applications.     

Enhancement of hard magnetic properties of BaFe12O19 nanoparticles

Barium hexaferrite nano particles are prepared through glycine assisted sol–gel auto combustion method with a minimal glycine to nitrate ratio and the pH values of 4, 6 and 9. X-ray diffraction patterns reveal the formation of hexagonal magneto-plumbite structure of BaFe₁₂O₁₉ with a weak intensity of secondary phase in the case of pH 4 and pH 6 samples. Interestingly disappearance of secondary phase at pH 9 sample is noticeable feature. Scanning electron microscope micrographs of the samples show the formation of characteristic hexagonal shape of barium hexaferrite. Constituent elements and chemical composition are analyzed using energy dispersive X-ray spectrum. Fourier Transform Infra Red and Raman spectra show the different metal–oxygen stretching vibration modes corresponding to octahedral, tetrahedral and trigonal bipyramidal sites of BaFe₁₂O₁₉. Magnetization studies show increase in saturation magnetization, squareness ratio, coercivity values on increasing the pH of the solution. 10 % enhancement of Curie temperature is observed (T_c = 495 °C of pH 9 sample) in comparison to its bulk counterpart T_c = 450 °C reported earlier. Enhancement of magnetic properties is achieved by optimizing pH and suitable choice of post annealing temperature during synthesis of nanoparticles of barium hexaferrite.     

Influence of temperature on structural and magnetic properties of Co0·5Mn0·5Fe2O4 ferrites

Co_0·5Mn_0·5Fe₂O₄ ferrites have been synthesized using a single-step sol-gel auto-combustion method in which the metal nitrate (MN)-to-citric acid (CA) ratio was adjusted to 0.5: 1 and pH to 7, respectively. The structural and magnetic properties of as-burnt and annealed samples were studied as a function of temperature. The inverse spinel structure was confirmed by X-ray diffraction (XRD) and crystallite size was estimated by the most intense peak (311) using Scherrer’s formula. Contrary to earlier studies reported in the literature, both as-burnt and annealed samples exhibit crystalline behaviour. Room temperature magnetic properties were studied using vibrating sample magnetometer (VSM) with field strengths up to ±10 kOe. Lattice constant and crystallite size increased as the annealing temperature was increased. However, the coercivity (H _c) initially increased and then decreased with the increase of crystallite size. The variation in coercivity is ascribed to the transition from a multi-domain to a single-domain configuration.     

Preparation of M-Ba-ferrite fine powders by sugar-nitrates process

In this paper, fine M-type barium hexaferrite (M-Ba-ferrite) particles were synthesized from sugar and nitrates by simple route, which revealed the feasibility of using sugar as chelating agent in forming solid precursors of BaFe₁₂O₁₉. The effects of factors, such as the molar ratio of Fe/Ba, calcination temperature and time, on the morphology, the phase component and the magnetic properties of M-type barium hexaferrite particles were studied by means of X-ray diffraction, infrared spectroscopy, transmission electron microscopy and physical property measurement system. The results showed that the molar ratio of Ba²⁺ to Fe³⁺ influenced significantly on the formation of the single phase barium ferrite. The hexagonal platelet barium ferrite particles with a specific saturation magnetization of 64.48 emu/g, remanence magnetization (Mr) of 33.84 emu/g, and coercive force (Hc) of 1848.85 Oe were obtained when the molar ratio of Fe/Ba was 11.5 and the calcination temperature was 1100 °C for 2 h.     

Influence of synthesis variables on the properties of barium hexaferrite nanoparticles

Barium hexaferrite (BaFe₁₂O₁₉) nanoparticles were synthesized by sol–gel auto-combustion route. Prepared samples were sintered at 950 and 1100 °C with Fe³⁺/Ba²⁺ = 12 and 20 mol ratio. The formation mechanism of barium hexaferrite was investigated by using X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analyses. In addition, the effect of temperature and Fe³⁺/Ba²⁺ mole ratio on BaFe₁₂O₁₉ formation and magnetic properties, and the effect of increasing the Fe³⁺/Ba²⁺ upon gel ignition and subsequent phase development were investigated. Finally the magnetic behavior was monitored with VSM. DSC studies showed that pure barium hexaferrite phase was formed from maghemite (γ-Fe₂O₃), without the formation of hematite (α-Fe₂O₃). Also, XRD results confirmed the formation of barium hexaferrite phase in non stoichiometric Fe/Ba ratio. VSM results showed that the saturation magnetization was decreased and coercivity increased with decreasing the grain size.