Barium Hexaferrite Research Articles

3D Printing of PLA/Magnetic Ferrite Composites: Effect of Filler Particles on Magnetic Properties of Filament

Three-dimensional printing is one of the most promising areas of additive manufacturing with a constantly growing range of applications. One of the current tasks is the development of new functional materials that would allow the manufacture of objects with defined magnetic, electrical, and other properties. In this work, composite magnetic filaments for 3D printing with tunable magnetic properties were produced from polylactic acid thermoplastic polymer with the addition of magnetic ferrite particles of different size and chemical composition. The used magnetic particles were cobalt ferrite CoFe2O4 nanoparticles, a mixture of CoFe2O4 and zinc-substituted cobalt ferrite Zn0.3Co0.7Fe2O4 nanoparticles (~20 nm), and barium hexaferrite BaFe12O19 microparticles (<40 µm). The maximum coercivity field HC = 1.6 ± 0.1 kOe was found for the filament sample with the inclusion of 5 wt.% barium hexaferrite microparticles, and the minimum HC was for a filament with a mixture of cobalt and zinc–cobalt spinel ferrites. Capabilities of the FDM 3D printing method to produce parts having simple (ring) and complex geometric shapes (honeycomb structures) with the magnetic composite filament were demonstrated.

Study of structural features and thermal properties of barium hexaferrite upon indium doping

Study of structural features and thermal properties of barium hexaferrite upon indium doping

The effect of agarose agent on the structural, magnetic and optical properties of barium hexaferrite nano-particles synthesized by sol-gel auto-combustion method

The main goal of this study is to improve the structural, magnetic and optical properties of the M-type barium hexaferrite nano-particles by addition of agarose as a natural agent, which were synthesized by the sol-gel auto-combustion method. For this purpose, properties of the synthesized samples were characterized by DTA-TGA, XRD, FT-IR, FE-SEM, TEM, VSM, and UV–Vis-DRS analyses. The DTA-TGA thermal analyses showed that agarose as a fuel agent could reduce the starting temperature of crystallization in the precursors. Also, based on these results, the temperature of 800 °C was chosen as the calcination temperature of the precursors. XRD patterns confirmed the formation of pure M-type barium hexaferrite without any impurities after calcination at 800 °C. The presence of agarose caused a more homogeneous distribution of metal cations Fe3+ and Ba2+ and the precursor was more easily and completely transformed into hexagonal barium ferrite in the presence of this agent. Also, the Rietveld refinement reported a decrease in average crystallite size from 49.4 to 29.6 nm by adding agarose. In addition, FE-SEM and TEM images showed that the agarose agent significantly reduces the average particle size and also prevents agglomeration of particles. Moreover, magnetic studies indicated that the presence of agarose led to the simultaneous increase of coercivity and remanence magnetization, resulting in an increase of maximum energy product from 0.81 to 0.92 MGOe. Also, the band gap energy (Eg) of the synthesized samples was found in the range of 2.36–2.76 eV. Finally, the significant effect of the agarose agent on the properties of BaFe12O19 nano-particles was clearly explained.

Synthesis of Superhydrophobic Barium Hexaferrite Coatings with Low Magnetic Hardness.

Using the multifunctional material barium hexaferrite as an example, the prospects for treatment at a quasi-equilibrium low temperature in an open atmosphere to form superhydrophobic magnetic coatings with pronounced crystalline and magnetic anisotropy have been demonstrated for the first time. The relationship between plasma treatment conditions, structural-phase composition, morphology, and superhydrophobic properties of (0001) films of barium hexaferrite BaFe12O19 on C-sapphire is studied. X-ray photoelectron spectroscopy (XPS), X-ray diffractometry (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), as well as magnetometry and moisture resistance analysis, were used as research methods. During plasma treatment with a mass-average temperature of 8-10 kK, intense evaporation and surface melting were observed, and texturing of the deposit along (0001) is found. When the treatment temperature was reduced to 4-5 kK, the evaporation of the material was minimized and magnetic and crystal anisotropy increased. However, the increase in the size of crystallites was accompanied by the transition of oxygen atoms from lattice nodes to interstitial positions. All samples exhibited low coercive fields below 500 Oe, associated with the frustration of the magnetic subsystem. Features of growth of materials with a wurtzite structure were used to form a superhydrophobic coating of barium hexaferrite. Plasma treatment regimes for obtaining self-cleaning coatings are proposed. The use of magnetically hard barium hexaferrite to radically change the properties of a coating is demonstrated herein as an example.

C-Axis-Oriented Ba(ZnHf)xFe12−xO19 M-Type Barium Hexaferrite with a High Squareness Ratio

C-Axis-Oriented Ba(ZnHf)xFe12−xO19 M-Type Barium Hexaferrite with a High Squareness Ratio

Influence of Ti-Al Substitution on Structure, Magnetic and Microwave Absorption Properties in Barium Hexaferrite

In order to investigate a new magnetic and microwave absorbing properties, barium hexaferrite materials of BaFe12O19 and BaFe10TiAlO19 were synthesized by solid state reaction (SSR) method. X-ray diffraction (XRD), Permagraph, and vector network analyzer (VNA) were used to probe the crystal structure, magnetic and microwave absorption properties. The results obtained that the barium hexaferrite structures have been shaped and showed high magnetic susceptibility and coercivity. Microwave absorbing properties of BaFe12O19 and BaFe10TiAlO19 absorbers were characterized at room temperature using VNA to record the reflected (S11) and transmitted spectrum (S21) for 7 – 13 GHz frequencies. Reflection loss (RL) and transmission loss (TL) of magnetic materials were calculated and performed the optimal absorption ability.

Effect of Annealing Atmosphere on Microstructure, Magnetic, and Microwave Properties of Barium Hexaferrite Thin Films

Effect of Annealing Atmosphere on Microstructure, Magnetic, and Microwave Properties of Barium Hexaferrite Thin Films

Effects of Ce-Zn co-substitution on the structural and magnetic properties of M-type barium hexaferrites

Herein, the effect of Ce-Zn substitution on the structure and magnetic properties of oriented barium M-type hexagonal ferrite (BaM) Ba1−xCexFe12−xZnxO19 (x = 0.0, 0.1, 0.2, 0.3, and 0.4) was investigated. XRD results show that when the Ce-Zn substitution amount exceeds 0.20, Fe2O3, CeO2 and BaFe16Zn2O27 impurity phases coexist in the BaM structure. As the Ce-Zn substitution content increases, the density (ds) of BaM tends to decrease, resulting in an increase in porosity. Correspondingly, Mr/Ms, Hc and K1 decreased monotonically with the increase of Ce-Zn substitution. In addition, the saturation magnetization Ms value first increased and then decreased with the increase of the substitution amount, and reached the maximum value when x = 0.1. Ha is the opposite of Ms and reaches a minimum at x = 0.1. The relatively satisfactory performances (Ms = 65.78 emu/g, Mr/Ms = 0.892 and Ha = 11,068 Oe) were detected in BaM at x = 0.1, which makes it a potential candidate for microwave devices.

Fabrication of binary to quaternary PVDF based flexible composite films and ultrathin sandwich structured quaternary PVDF/CB/g-C3N4/BaFe11.5Al0.5O19 composite films for efficient EMI shielding performance

This work reports the facile fabrication of binary, ternary, and quaternary polymer composite films using combinations of Polyvinylidene fluoride (PVDF), Carbon Black (CB), Graphitic carbon nitride (g-C3N4), and Aluminum doped Barium hexaferrite (BaFe11.5Al0.5O19) nanoplatelets for application as EMI shielding materials at X-band frequency. The excellent total EMI-SE of 47.39 dB in X-band for ultra-small thickness of 0.193 mm was observed for the quaternary PVDF/CB/g-C3N4/BaFe11.5Al0.5O19 composite film. The quaternary composite film was further hot pressed into sandwich-structured two-layer and three-layer composite films. The sandwich and/or multi-layered structure of the PVDF/CB/g-C3N4/BaFe11.5Al0.5O19 composite film improved the EMI shielding performance through multiple reflection loss. With the addition of intact conduction of fillers and multiple-reflection-absorption effect, the multi-layered composite structure attained the best shielding efficiency (SE) of 64.54 dB.

Synthesis of Substituted Barium Ferrites and Hexaferrites and Their Electrochemical Characterization

Magnetic nanoparticle has been an attractive area of research in view of their unique physical and chemical properties. [1] In the field of electrochemistry, particularly electroanalysis, they are extensively used as functional materials due to their high surface area, mass transport, catalytic effect, and control over the local environment. Barium based ferrites have emerged as attractive materials of interest due to their interesting physical, chemical, magnetic and electrical properties. [2] Hexaferrite and ferrites such as barium ferrite are very important group of magnetic oxides and these are used in different technologies including sensors because of their specific properties such as low cost, corrosion resistance chemical stability and large magneto crystalline anisotropy. [3] However, the investigation of the effect by various other elements on the structure of hexaferrite and ferrite particles and its electrochemical properties remains the subject of popular research. In this work, mixed metallic oxides hexaferrite and ferrite were synthesized by sol–gel combustion route using glycerin as an adjuvant. [4] Their structure was confirmed by means of X-ray powder diffraction. Scanning electron microscopy were used to investigate the morphology of the sample and the vibrations of the functional groups were determined by Raman and IR-ATR spectroscopy. The electrochemical behavior of substituted hexaferrite and ferrite were determined by cyclic voltammetry using an Ag/AgCl electrode, platinum wire and a glass carbon electrode (GCE), as reference electrode, counter electrode and working electrode, respectively. The GCE was modified with mixed metal oxides obtained to analyze their electrochemical behavior.Bibliographic Xueli X, Wei S 2019 Materials Technology, 1-5Kefeni, K.K.; Msagati, T.A.; Mamba, B.B. 2017, Sci. Eng. B. 215, 37–55Valenzuela R, Magnetic Ceramics, Chemistry of Solid State Materials 4 serie. Cambridge (Great Britain): Cambridge University Press, 1994, p. 50Sandra F. Basante-Delgado, Dalliver González-Vidal, Jimmy A. MoralesMorales, William A. Aperador-Chaparro, Jairo A. Gómez-Cuaspud, 2020 Phys.: Conf. Ser. 1541 012013

Influence of Manganese Doping on Optical Properties of Barium Ferrites Nanoparticles

The barium hexaferrite magnetic materials Mn-doped BaZn1+x Mnx Fe12-2x O19 (x = 0.4, 0.8, 1.2, 1.6, and 2) were prepared using the ceramic method. The powder samples ferrite were subjected to XRD, FT-IR, and UV-Vis to investigate the nanoparticles' structural changes. UV–Vis spectroscopy is used to obtain the samples' absorption spectrum and calculate the band gap energy. X-ray diffraction patterns and FT-IR investigations confirmed the formation of a single-phase M-type hexagonal structure. The grain size was measured from Scherrer's equation, and it is found in the range of 43-56 nm, with increasing the concentration of Mn ions, which shows the enhancement in the degree of crystallinity and increase in the size of grain size. UV-vis spectroscopy was used to confirm the formation of the BaZn1+x Mnx Fe12-2x O19 nanoparticles. The transmission was found to increase slowly in the 200-290 nm wavelength and then decreased to 332 nm after that increase until the maximum for all samples was about 99% in 480-800 nm wavelengths. The highest transmission will be exclusively used for window layers in solar cells. The band gap energy increased gradually with a rise in Mn ions and a decrease in Zn ion concentration. The refractive index, dielectric constant, and optical dielectric constant decreased with an increase in Mn ions and a decrease in Zn ions concentration.

Microscopic mechanism of ferroelectric properties in barium hexaferrites

The microscopic mechanism of the occurrence of ferroelectric properties in M-type barium hexaferrites is investigated by experimental and first-principle computation methods. The analysis of magnetic, X-ray, and Mössbauer measurements of BaFe12O19 samples ascertains the correlation between the thermal factor in the process of annealing samples and their functional properties. The occurrence of the remnant polarization in barium hexaferrites at room temperature contradicts the description of their crystal structure in the framework of centrosymmetric space group P63∕mmc (No. 194), in which one of the symmetry operations is inversion center. Therefore, the crystal structure of BaFe12O19 was analyzed in the frameworks of SG P63∕mmc (No. 194) and non-centrosymmetric SG P63mc (No. 186). The computed value of polarization for a non-centrosymmetric unit cell is ∼ 3.5 μC∕cm2. The analysis of polarization was carried out on a path connecting the polar P63mc and non-polar P63∕mmc structures and considered in terms of the total energy barrier. Our result allows ascertaining a direct relationship between the remnant polarization of the unit cell and the broken spatial-inversion symmetry in the crystal structure of M-type barium hexaferrite.

Paste-Injection of Low-Density Barium Hexaferrite Magnets with Soft Magnetic Iron Phase

Permanent magnets of varying shapes and sizes are increasingly produced. For hexaferrite magnets, it is challenging to incorporate polymers and a soft magnetic phase in the form of paste before injection molding or extrusion free-forming. In this study, hard magnetic barium hexaferrite/soft magnetic iron composites with a density of 2.28–2.34 g/cm3 are obtained after paste-injection molding and subsequent sintering at 1150 °C for 5 h. Variations of the binder (143.5–287.0 mg poly(vinyl alcohol), PVA) and the plasticizer (75–150 mg poly(ethylene glycol), PEG-400) in the ceramic–polymer paste give rise to comparable remanent magnetization (33.10–33.63 emu/g) and coercivity (3854–3857 Oe). Unlike all-ferrite systems, the presence of a soft magnetic metal phase is not detrimental to the coercivity. However, the remanent and saturation magnetizations are not substantially increased. The addition of 1% and 5% of iron oxide in the ceramic–polymer paste gives rise to hard/soft composites with lower densities of 2.11 and 2.14 g/cm3. The coercivity is increased to 3942–3945 Oe; however, the maximum energy product is reduced.

Synthesis of Ni doped barium hexaferrite by microemulsion route to enhance the visible light-driven photocatalytic degradation of crystal violet dye

The pristine and Ni doped BaNixFe12-xO19 (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) NPs have been fabricated via facile microemulsion approach and the impact of dopants was explored based dielectric, optical, structural and the photocatalytic properties of BaNixFe12-xO19 nanoparticles. X-ray diffraction and Raman study confirmed the formation of regular hexagonal geometry with space group P63/mmc with crystallite size in 32–50 nm range. Functional groups were identified using FTIR analysis. The remanence (Pr), saturation polarization (Ps) and coercivity (Hc) was explored by P-E loop analysis and the value of Pr and Ps was enhanced with the concentration of dopant. According to PL spectra, highly doped materials had a higher charge separation (e−- h+) and low recombination rate, which resulted in higher photocatalytic degradation activity of fabricated nanomaterials. The optical band gap was found to be 1.78 eV versus undoped (2.60 eV for pristine BaFe12O19). Due to polarizations, the dielectric loss, dielectric constant and tangent loss values were declined, while AC conductivity was enhanced. Photocatalytic performance of doped and undoped samples under visible right irradiation was studied for crystal violet dye. For 100 min exposure to visible light, the highly doped catalyst exhibits 97% degradation versus 60% in case of pristine this is attributed to efficient electron-hole pair separation. Furthermore, quenching effect of different scavengers indicated that hydroxyl radical had a main role, and e− or h+ played a minimal role in CV dye degradation. The enhanced properties due to doping make BaNixFe12-xO19 a potential candidate for photocatalytic applications under visible light irradiation.

Increased Electromagnetic Wave Absorption through Controlled Sonication Processing on BaFe11.2Mg0.4Al0.4O19 Nanoparticles

Electromagnetic waves show rapid development in electronics, telecommunications, and the military. One of the efforts to overcome the effects of electromagnetic interference is by developing microwave-absorbing materials. Barium hexaferrite is the best candidate for development as an absorber material. Microwave absorption in barium hexaferrite can be increased through Mg-Al doping and reducing the particle size. This study aimed to analyze sonication parameters to reduce the particle size by combining destruction methods using mechanical alloying followed by high-power ultrasonic irradiation. Barium hexaferrite was synthesized through mechanical alloying by mixing stoichiometric BaCO3, Fe2O3, Al2O3, and MgO (Sigma-Aldrich p.a 99%) (Mg-Al 0.4%wt). The samples continued the sintering process at 1200 °C for 2 h to grow crystal embryos. The optimal parameters for ultrasonic destruction were using a transducer:reactor diameter ratio of 1:10, a particle density of 5 g/250 mL, and adding a non-ionic surfactant of 0.01% at an amplitude of 55% and a sonication time of 8 h. These methods resulted in the saturation magnetization of 18.50 emu/g and a coercivity of 0.08 Tesla. The reduction in the particle size of BHF doped with Mg-Al was successfully up to 21 nm, resulting in a reflection loss of up to −40.8697 dB at 11.896 GHz (x-band, 8–12 GHz). The BHF nanoparticles doped with Mg-Al effectively absorbed up to 99.99% electromagnetic waves.

Miniature magneto-optic angular position sensor.

This Letter describes a miniature Fabry-Perot, contactless, magneto-optic sensor for angular position measurement. The sensor utilizes a magneto-optic fluid comprising barium hexaferrite nanoplatelets that become birefringent in the presence of an external magnetic field and a compact fiber-optic sensor system for tracking the liquid's optical axis direction. An efficient temperature compensation system is provided which allows the use of otherwise highly temperature-sensitive magneto-optic liquids. An unambiguous measurement range of 90° and a resolution of better than 0.05° are demonstrated experimentally.

Synthesis, characterization, and investigation of electrochemical hydrogen storage capacity in barium hexaferrite nanocomposite

Hydrogen is considered as one of the most renewable and also efficient fuels. When hydrogen is burned, its only product is water. But the most important issue in the use of hydrogen is its storage. Hydrogen must be stored reversibly in a way that is completely safe and has high storage efficiency. Due to obtaining high-efficiency hydrogen storage, new nanostructures based on barium hexaferrite nanostructures (BaFe12O19) and functionalized multi-walled carbon nanotubes BaFe12O19 nanocomposite (BaFe12O19/MWCNTs) are synthesized via sol-gel combustion method. The nanocomposites are confirmed through Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller (BET), and vibrating sample magnetometer (VSM) techniques. Further, the hydrogen storage capacity of BaFe12O19/MWCNTs nanocomposite is assessed by chronopotentiometry analysis (CHP). The XRD studies demonstrates that the average crystallite sizes of the BaFe12O19 and nanocomposite are estimated to be about 16.3 and 7.6 nm, respectively. Also, the VSM measurement shows a saturation magnetization values (Ms) of 20.1 and 1.3 emu/g for BaFe12O19 and BaFe12O19/MWCNTs nanocomposite, respectively. The electrochemical consequences indicate that the BaFe12O19/MWCNTs nanocomposite has a high capacity for hydrogen storage and discharge rate. The maximum discharge capacity of BaFe12O19/MWCNTs nanocomposite reaches about 360 mAh/g in the first cycle to approximately 3600 mAh/g after 20 cycles under an optimal current of 2 mA. As a result, the BaFe12O19/MWCNTs nanocomposite showed a good capacity as a promising active ingredient for hydrogen storage devices.

Barium hexaferrites with narrow ferrimagnetic resonance linewidth tailored by site‐controlled Cu doping

AbstractBarium hexagonal ferrites exhibiting unique self‐biasing characteristics have great potential for application in planar microwave devices, such as self‐biased circulators. Cu doping is an effective method to tailor their anisotropy field and ferrimagnetic resonance (FMR) linewidth to meet the requirements for low‐frequency low‐loss microwave devices. However, the regulation mechanism of Cu doping is still obscure, and its regulation effect is not optimized. Here, the magnetic and microwave properties of two groups of barium hexaferrites with site‐controlled Cu doping are reported. The diffusion dynamics of Cu2+ ions are comprehensively investigated, revealing significant differences in the concentration distribution and polycrystalline morphology, when comparing CuO as a reactant and sintering additive. The accumulation of Cu2+ ions at grain boundaries contributes to the increase in coercivity, whereas the dispersion of Cu2+ ions in crystallites leads to the decrease in the anisotropy field. Moreover, by introducing Cu2+ ions into the interstitial positions of the lattice, barium hexaferrites with a narrow FMR linewidth of 303 Oe and a high remanence ratio of 0.82 are achieved. These results represent the lowest FMR linewidth reported in polycrystalline hexagonal ferrites and prove the great technological value and commercial potential of Cu‐doped barium hexaferrites for next‐generation planar microwave devices.

Polar Nano-Domains in Barium Hexaferrite Revealed with Multislice Electron Ptychography

Polar Nano-Domains in Barium Hexaferrite Revealed with Multislice Electron Ptychography

Investigation of Mg-Doped Y-Type Barium Hexaferrite Using Mössbauer Spectroscopy

Y-type barium hexaferrite Ba <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Co <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2-<i>x</i></sub> Mg <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>x</i></sub> Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">22</sub> ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$x $ </tex-math></inline-formula> = 0, 0.1, 0.3, 0.5) was prepared by conventional solid-state reaction method. The samples were sintered first at 1100 °C and then at 1150 °C to obtain the single phase Ba <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Co <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2-<i>x</i></sub> Mg <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>x</i></sub> Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">22</sub> samples. To observe the crystal structure of the prepared sample, X-ray diffraction (XRD) with Cu- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{K}\alpha $ </tex-math></inline-formula> ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula> = 1.5406 Å) was used. The analysis of the XRD patterns showed that the Ba <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Co <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2-<i>x</i></sub> Mg <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>x</i></sub> Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">22</sub> is hexagonal in the R-3m space group. To investigate the magnetic properties, a vibrating sample magnetometer (VSM) and Mössbauer spectroscopy were utilized. The hysteresis loops and the zero field cooled-field cooled (ZFC-FC) curves of the samples were obtained via VSM. The results of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$M$ </tex-math></inline-formula> – <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$H$ </tex-math></inline-formula> experiment showed that, the saturation magnetization ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$M_{\mathrm {s}}$ </tex-math></inline-formula> ) and the coercivity ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$H_{\mathrm {c}}$ </tex-math></inline-formula> ) decreased with increasing Mg <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\mathrm {2+ {}}}$ </tex-math></inline-formula> concentration. The spin reorientation temperature ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$T_{\mathrm {s}}$ </tex-math></inline-formula> ) was observed in the ZFC-FC curves obtained through temperature-dependent magnetization experiments. The <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$T_{\mathrm {s}}$ </tex-math></inline-formula> was decreased from 215 to 202 K as the substitution of Mg <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> ions increased. The Mössbauer spectra were obtained using Mössbauer spectroscopy. The Mössbauer experiments were conducted from 4.2 to 295 K. The results of the Mössbauer experiments at various temperatures showed that the magnetic hyperfine fields ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$H_{\mathrm {hf}}$ </tex-math></inline-formula> ) decreased with an increase in temperature. The isomer shift ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\delta$ </tex-math></inline-formula> ) values maintained at approximately 0.1–0.4 mm/s. The ion state of the iron at all temperatures was Fe <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> . The quadrupole splitting ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta E_{\mathrm {Q}}$ </tex-math></inline-formula> ) values were stably maintained; however, they changed abruptly at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$T_{\mathrm {s}}$ </tex-math></inline-formula> .