Non stoichiometric Strontium ferrite nanoparticles and magnetic measurement (original) (raw)
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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.
IMPEDANCE AND MAGNETIC PROPERTIES OF STRONTIUM HEXAFERRITE NANOPARTICLES
International Journal of Trendy Research in Engineering and Technology, 2017
Magnetic nanoparticles are important physical systems, relevant for many applications, and in many cases the starting point of fundamental developments in Nanomagnetism. Strontium ferrite enjoys a high degree of chemical stability and is completely nontoxic, which makes it ideal for a wide range of applications. Magnetoplumbite-type (M-type) strontium ferrite particles have been synthesized via the sol-gel technique employing ethylene glycol as the gel precursor. The Phase, morphology and particle diameter and the magnetic properties of samples were studied by x-ray diffractometry (XRD), Scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) respectively. X-ray powder diffraction patterns showed that the samples were single-phase with the space group of P63/mmc. The magnetic properties such as coercivity, saturation magnetization and remenant magnetization of the samples were found to be 6405.2 Oe, 28.256 and 15.2 emu/g, respectively. The thermal behaviour of the nano particles was studied using thermogravimetric analysis (TGA). The impedance analysis using complex impedance spectroscopy (CIS) technique reveals negative temperature coefficient of resistance behavior of the prepared Strontium hexaferrite nano particles.
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.
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.
Nanoscale research letters, 2018
Synthesis of nanocrystalline strontium ferrite (SrFeO) via sol-gel is sensitive to its modification parameters. Therefore, in this study, an attempt of regulating the pH as a sol-gel modification parameter during preparation of SrFeO nanoparticles sintered at a low sintering temperature of 900 °C has been presented. The relationship of varying pH (pH 0 to 8) on structural, microstructures, and magnetic behaviors of SrFeO nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning microscope (FESEM), and vibrating sample magnetometer (VSM). Varying the pH of precursor exhibited a strong effect on the sintered density, crystal structure and magnetic properties of the SrFeO nanoparticles. As the pH is 0, the SrFeO produced relatively largest density, saturation magnetization, M, and coercivity, H, at a low sintering temperature of 900 °C. The grain size of SrFeO is obtained in the range of 73.6 to 133.3 nm. The porosity of the sample affected the density and th...
IEEE Transactions on Magnetics, 2009
Substituted strontium ferrites SrFe 12 x Mg x 2 Sn x 2 O 19 (x = 1, 2 and 3) were prepared by sol-gel method. X-ray diffraction (XRD), transmission electron microscope (TEM), AC susceptometer, vibrating sample magnetometer (VSM) and vector network analyzer were used to analyze the structure, static and dynamic magnetic properties of the prepared samples. The prepared ferrite particles possess irregular non spherical shape with a broad size distribution. The substitution was very effective in reducing coercive field. Based on microwave measurements of reflectivity, SrFe 12 x Mg x 2 Sn x 2 O 19 is a good candidate for electromagnetic compatibility and other practical applications at high frequencies.
Journal of Crystal Growth, 2006
Sr-hexaferrites with the addition of SiO 2 (0-2.0 wt%) have been prepared by the solid-state reaction method. The structural characterization of the samples confirmed the major phase of Sr-hexa-ferrite. The average grain size was found within the range of micron. The coercivity increased up to 1.5 wt% of silica addition and then decreased. Remanence has decreasing trend with the increase of silica percentage. The DC electrical properties were studied as a function of temperature. Activation energy and drift mobility were determined. The room temperature electrical resistivity increased from 5.95 Â 10 8 to 1.76 Â 10 9 (O-cm), which in turn increased the activation energy with the successive addition of SiO 2 . The dielectric properties as a function of frequency, under normal conditions, were also measured. From 80 Hz to 1 MHz the dielectric constants and loss factors remained within the range of 3340-12 and 5.75-0.21, respectively. (S. Hussain), tpl.qau@usa.net (A. Maqsood).
Journal of Alloys and Compounds, 2010
Strontium hexaferrite samples of different composition were prepared by the self-combustion method and heat treated in air at 1100ºC for two hours: SrFe 12 O 19 (S0), Sr 0.7 Nd 0.3 Fe 11.7 Co 0.3 O 19 (SS), Sr 0.7 Nd 0.3 Fe 10.7 Co 0.3 O 19 (SM) and Sr 0.7 Nd 0.3 Fe 8.4 Co 0.3 O 19 (SL). The phase identification of the powders was performed using XRD. Only sample SL (with the lowest iron concentration) shows well-defined peaks of the hexaferrite phase with no secondary phases. Nd-Co substitution modifies saturation magnetization (M S) and coercivity (H c) but only samples with low Fe 3+ content (SL and SM) show the best magnetic properties, indicating that the best results for applications of this ferrite will be obtained with an iron deficiency in the stoichiometric formulation.
International Journal of Modern Physics B
In this research, SrFe[Formula: see text]Ni[Formula: see text]O[Formula: see text] (x [Formula: see text] 0 − 1) hexagonal ferrites were prepared by sol-gel auto-combustion method. Effect of Ni substitution on structural, morphological and magnetic properties of nanoparticles was investigated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM), respectively. The XRD results confirmed that all samples with x [Formula: see text] 0.5 have single phase M-type strontium ferrite structure, whereas for the SrFe[Formula: see text]Ni[Formula: see text]O[Formula: see text] samples with x [Formula: see text] 0.5, the spinel NiFe2O4 phase has also appeared. The lattice parameters and crystallite sizes of the powders were concluded from the XRD data and Williamson–Hall method. Magnetic analyses showed that the coercivity of powders decreased from 5672 Oe to 639 Oe while the saturation magnetization increas...
Study of strontium ferrites substituted by lanthanum on the structural and magnetic properties
Ceramics International, 2012
M-type strontium ferrites, Sr 0.8 La 0.2 Fe 12 O 19 have been synthesized by conventional ceramic process. The effects of lanthanum addition and sintering temperature on microstructures and magnetic properties of SrFe 12 O 19 and Sr 0.8 La 0.2 Fe 12 O 19 samples were investigated. Microstructural analysis of the SrFe 12 O 19 and Sr 0.8 La 0.2 Fe 12 O 19 specimens, sintered at different temperatures revealed that average grain sizes of SrFe 12 O 19 ferrites were larger than that of Sr 0.8 La 0.2 Fe 12 O 19 ferrite and increased with increasing sintering temperature. The X-ray diffraction (XRD) results confirmed the strontium hexagonal ferrite phase of SrFe 12 O 19 and Sr 0.8 La 0.2 Fe 12 O 19 compounds. A maximum coercivity value of 4850 Oe and maximum saturation magnetization value of 102 emu/g were obtained for the SrFe 12 O 19 ferrite sintered at 1150 8C and for the SrFe 12 O 19 and Sr 0.8 La 0.2 Fe 12 O 19 ferrites sintered at 1300 8C, respectively. The remanence (Mr) of Sr 0.8 La 0.2 Fe 12 O 19 sample sintered at 1200 8C possesses the maximum value of 60 emu/g.