Synthesis and characterizations of Nd3+ doped SrFe12O19 nanoparticles (original) (raw)
Related papers
Academic Pubilication Council of Kuwait University , 2023
In this proposed work, the strontium ferrite (SrFe 2 O 4) nanoparticles were successfully synthesized in the presence of strontium nitrate (Sr (NO 3) 2) and ferric nitrate (Fe (NO 3).9H 2 O) as primary sources by using chemical coprecipitation method. The prepared powders were kept different calcinations temperature (650, 750 and 850 C) and characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) techniques. The XRD patterns demonstrated the cubic and orthorhombic phase of spinel formation and FTIR transmittance spectra confirmed the presence of strontium ferrite related molecular functional groups. Further, SEM micrograph showed spherical nanoparticles with less agglomerated structure. VSM studies revealed the hard magnetic properties with the highest saturation magnetization (Ms), remanent magnetization (M r) and coercivity (H c) of 22.17 emu/g, 11.807 emu/g and 5662.6 Oe respectively by VSM.
Influence of High Temperature on the Crystal Structure of SrFe12O19 Nanoparticle
Journal of Nanomaterials
In this study, strontium hexaferrite nanoparticles synthesized by sol–gel autocombustion method and the effect of high annealing temperature on produced nanoparticle have been studied. Powders were annealed at 1,000 and 1,300°C. Structural properties of synthesized powders were analyzed by X-ray diffraction (XRD). Hexagonal structure and shape of SrFe12O19 nanoparticles were analyzed from field-emission scanning electron microscope and transmission electron microscope figures. Fourier-transform infrared spectroscopy confirmed the formation of an M-type hexagonal structure. The thermal behavior of nanoparticles has been investigated by thermogravimetric analysis (TGA and DTG). Height measurement of nanoparticles with 2D and 3D images of the surface obtained from atomic force microscopy. XRD pattern of strontium hexaferrite nanoparticle was used for determining the crystal structure and examining the effect of high annealing temperature on powders by finding lattice parameters, densit...
Structure and Magnetic Properties of SrFe12O19/CoFe2O4 Nanocomposite Ferrite
VNU Journal of Science: Mathematics - Physics
Nanocomposite particles SrFe12O19/ CoFe2O4 were synthesized by sol-gel method. The nanocomposites are formed at the calcining temperature around 850 o C in 5 hours. The phase composition, surface morphology and magnetic properties of the nanocomposites were investigated using XRD, SEM and VSM, respectively. The results show that the magnetic properties of nanocomposite particles are strongly influenced by the molar ratios of the hard and soft phases and particle size distributions. The samples with the mass ratio of Rm= SrFe12O19/ NiFe2O4 = 1/3 and 1/5 are characterized with a "bee waist" type hysteresis loop. While all the samples RV show an excellent smooth hysteresis loop and a singlephase magnetization behavior. The coercivity decreases significantly and the magnetization drastically increases with decreasing of volume ratio RV.
Journal of Physics D: Applied Physics, 2020
Strontium hexaferrite nanocrystalline powders were synthesized using a citrate combustion method and subsequently subjected to post-synthesis processing with the aim of tuning the micro-nanostructure to improve the magnetic properties. Firstly, the synthesis thermal treatments were optimized in order to minimize the formation of secondary phases, mainly hematite. Secondly, the as-synthesized powders were conditioned by a two-step process: ball milling in wet medium (ethanol) and high-speed mixing. The final processed powders exhibited a saturation magnetization of 74 emu g−1 and a coercivity of 6450 Oe. Following a low-temperature combustion synthesis, the coercivity is one of the largest values reported for strontium ferrites. The combination of the two-step conditioning procedure results in a useful methodology to obtain SrFe12O19 nanocrystalline powders with competitive properties. The morphological, structural and magnetic properties of the processed material make it a promising...
Materials Research Bulletin, 2015
The influence of ball milling and subsequent sintering of a 3:1 molar mixture of SrCO 3 and a-Fe 2 O 3 on the formation of Sr 3 Fe 2 O 7Àd double perovskite is investigated with different analytical techniques. Milling the mixture for 110 h leads to the formation of SrCO 3-a-Fe 2 O 3 nanocomposites and the structural deformation of a-Fe 2 O 3 via the incorporation of Sr 2+ ions. Subsequent sintering of the pre-milled reactants' mixture has led to the partial formation of an SrFeO 3 perovskite-related phase in the temperature range 400-600 C. This was followed by the progressive development of an Sr 3 Fe 2 O 7Àd phase that continued to increase with increasing sintering temperature until a single-phased nanocrystalline Sr 3 Fe 2 O 7Àd phase was attained at 950 C (12 h). This temperature is $350 C lower than the temperature at which the material is prepared conventionally using the ceramic method. The evolution of different structural phases during the reaction process is discussed. Rietveld refinement of the X-ray diffraction data shows a value of 0.60 for the oxygen deficiency d, in consistency with the Fe 3 + /Fe 4+ ratio derived from the 57 Fe Mössbauer data recorded at both 300 K and 78 K. The Mössbauer data suggests that the Sr 3 Fe 2 O 6.4 nanoparticles are superparamagnetic with blocking temperatures below 78 K. The surfaces of the Sr 3 Fe 2 O 6.4 nanoparticles were shown to have a complex structure and composition relative to those of their cores with traces of SrCO 3 , SrO and SrFeO 3Àd being detected.
Optical, Thermal and Magnetic Properties of Strontium Ferrite Nanoparticles
Iranian Nanotechnology Society, 2022
This study endeavors to investigate the influence of calcination temperatures (650, 750 & 850°C) on the strontium ferrite (SrFe2O4) nanoparticles synthesized by the co-precipitation method. The prepared powder samples were characterized by various measurement techniques such as X-ray diffractometer (XRD), scanning electron microscopy (SEM), thermo gravimetric analysis (TGA), and vibrating sample magnetometer (VSM). Initially, the XRD patterns were confirmed the presence of spinel SrFe2O4 phases. Overall, the number of diffraction peaks increased due to the enhancement of calcination temperature. The SEM morphological features are shown the spherical-shaped nanoparticles with less agglomeration. Considerably, the agglomeration between the nanoparticles increased due to the higher calcination temperatures. However, the structural and morphological investigation was helpful and carried out for the TGA and VSM investigation. At 850°C calcination temperature, TGA revealed 5.8% of weight loss and VSM endorsed the magnetic properties such as high saturation magnetization (Ms), remanent magnetization (Mr) and coercivity (Hc) come out to be 37.26 emu/g, 19.788 emu/g and 6188.4 Oe, respectively.
Nanomaterials, 2022
In this study, SrFe12-xNdxO19, where x = 0, 0.1, 0.2, 0.3, 0.4, and 0.5, was prepared using high-energy ball milling. The prepared samples were characterized by X-ray diffraction (XRD). Using the XRD results, a comparative analysis of crystallite sizes of the prepared powders was carried out by different methods (models) such as the Scherrer, Williamson–Hall (W–H), Halder–Wagner (H–W), and size-strain plot (SSP) method. All the studied methods prove that the average nanocrystallite size of the prepared samples increases by increasing the Nd concentration. The H–W and SSP methods are more accurate than the Scherer or W–H methods, suggesting that these methods are more suitable for analyzing the XRD spectra obtained in this study. The specific saturation magnetization (σs), the effective anisotropy constant (Keff), the field of magnetocrystalline anisotropy (Ha), and the field of shape anisotropy (Hd) for SrFe12-xNdxO19 (0 ≤ x ≤ 0.5) powders were calculated. The coercivity (Hc) increases (about 9% at x = 0.4) with an increasing degree of substitution of Fe3+ by Nd3+, which is one of the main parameters for manufacturing permanent magnets.
Evidence of existence of metastable SrFe12O19 nanoparticles
Journal of Magnetism and Magnetic Materials, 2011
The existence of metastable hexaferrite is reported. Synthesis of strontium hexaferrite, SrFe 12 O 19 , at 400 1C was realized under controlled oxygen atmosphere. Such technique allows obtaining of SrFe 12 O 19 at lower temperatures than those by traditional methods (above 800 1C). Phase transformation occurred during a measurement of magnetization vs. temperature (heating up to 625 1C). The heat treatment induces a change from SrFe 12 O 19 to g-Fe 2 O 3 (as the main phase), and SrFeO 2.74 to Sr 2 Fe 2 O 5 .
Strontium ferrite nanoparticles
Pure phase and mixed phase strontium hexa ferrite powder were prepared using citrate precursor method. The annealing temperature for both samples was 450 o C. The samples were structurally characterized using X-Ray diffractometer(XRD) and magnetically characterized using Vibrating sample magnetometer (VSM). The particle size was observed 15 nm and 8nm at same annealing temperature 450 o C. Some additional phase appears in addition to hexaferrite. The retentivity and magnetization was found 3.321 emu/g, 36.615 emu/g for pur phase sample while 0.64 emu/g and 33.332 emu/g for mixed phase sample respectively. This behaviour suggests that non-stoichiometric preparation as a possible route for engineering preparation of samples for a particular set of magnetic parameter values. In these samples we observed a change in retentivity that seemed independent of magnetization.
Journal of Inorganic and Organometallic Polymers and Materials, 2020
The strontium ferrite nano-crystals were prepared via co-precipitation method in different synthesis media including a mixture of ethanol and water (with a volume ratio equal to 3:1) and water. In this way, the iron and strontium chlorides with various molar ratios were utilized as sources for Fe 3+ and Sr 2+ ions, respectively. Phase analyses, structural properties and morphology of the SrFe 12 O 19 powders were characterized by various techniques including X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometer and Fourier transform infrared spectra. Thermal decomposition behaviors of the as-synthesized precursors were monitored by DTA/TGA (differential thermal analysis/thermo-gravimetric analysis). The effects of molar ratio, calcination temperature and co-precipitation media of the strontium ferrite powder were investigated. The results of DTA indicated that the strontium hexaferrite prepared by co-precipitation in ethanol/water media was formed at a lower temperature. The maximum saturation magnetization of the strontium ferrite powder with the value of 58 emu/g was achieved at a temperature of 950 °C by a Fe 3+ /Sr 2+ molar ratio of 12. Wide coercivity in the range of 1512-5764 Oe was observed by tuning calcination temperatures. Furthermore, the photocatalytic properties of the resultant optimum SrFe 12 O 19 particles were assessed. The destruction of methylene blue dye was about 46% in the presence of the strontium ferrite under UV light irradiation for 120 min.