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In this paper, Y-type strontium hxaferrite (Sr₂Co₂Fe₁₂O₂₂) nanostructure with molar ratio of citric acid to metal nitrats of 1:0.5, 1:1, 1:1.5 and 1:2 prepared using a sol-gel of auto-combustion method and then prepared powders were sintering at 1000  ˚C for 3 h. In order to investigate structural, magnetic and dielectric properties of the Sr₂Co₂Fe₁₂O₂₂ nanostructure, samples have been analyzed by X-ray diffraction analysis (XRD), Fourier transforms infrared spectroscopy (FT-IR), scanning electron microscopy field emission (FESEM) , vibrating sample magnetometer (VSM) and LCR meter methodes. The results of measurements of structur show that Y-type hexaferrite structural in the samples with  molar ratios of 1.5 and 2 was completely formed, so that in the sample with molar ratio of 1.5 peaks and its intensity is closer to the standard card. Also, the results of dielectric reveal that by increasing frequency, dielectric constant and dielectric loss decreases which indicates that samples could be suitable for use in devices.  The results show that the best papered sample is at temperature and time of 1000- 3h, respectively, with citric acid mole ratio of 1_.5.

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In this research, Graphene/ Bismuth aerogel nanocomposite was fabricated by hydrothermal method and it’s structural, magnetic and photocatalytic properties were investigated. For this purpose, aerogel of nanocomposites were prepared with a concentration of 4 for graphene oxide and concentrations of 0.2, 0.5 and 1 mg/ml for Bismuth ferrite. Phase and structural studies with XRD and FT-IR analyzes confirm the formation of bismuth ferrite with a rhombohedral structure of perovskite type and reduction of graphene oxide. The SEM images show the porous structure of graphene aerogel well. TEM analysis confirms the composite of bismuth ferrite nanoparticles in the structure of graphene aerogel. The energy gap of the samples was calculated from the results of UV-Visible spectroscopy. Based on the parameter measured by the vibrating sample magnetometer (VSM), it shows a decrease in the magnetization saturation of bismuth ferrite nanoparticles after composite with graphene aerogel. Methyl blue decomposition was evaluated by bismuth ferrite nanoparticles and graphene/ferrite bismuth nanocomposites using UV-Vis apparatus. The best photocatalytic performance of graphene/bismuth ferrite aerogel is in the sample with 0.5 mg/ml concentration.
 

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In this paper, the nanoparticles of FeNi₃ were prepared by hydrothermal and co-precipitation methods. Also, different times and temperatures with different amounts of the hydrazine reducing hydrate were investigated in hydrothermal method. After fabrication of the samples by two methods, the samples have been characterized using the x-ray diffraction analysis (XRD), the field emission scanning electron microscopy (FESEM), and magnetic properties of the samples using a vibrating sample magnetometer (VSM). The results of diffraction pattern show that the amount of hydrazine hydrate used is very effective in single-phase sampling. FESEM images show nanoparticles, but at some temperatures and times, particles are not formed or stickiness and melting are observed. The results of VSM analysis show that the samples have high magnetic properties in both methods and not much change in saturation magnetization between samples was seen in both methods.
 

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In this study, the effect of surfactant on the structural and photocatalytic properties of bismuth ferrite made (BiFeO₃) by hydrothermal method at a temperature of 180 °C and a concentration of 4 M was investigated. The surfactants studied in this paper are ethylene glycol and sodium dodecyl sulfate. The results of diffraction pattern analysis showed that the samples have a rhombic perovskite structure distorted with space group R3c. Also, high purity bismuth ferrite was made at 180 °C and 4M concentration without the presence of surfactant. FESEM results showed that the particle size decreased with the presence of surfactant. The optical and photocatalytic properties of the samples were also investigated by UV-Visible analysis. The results showed that the amount of optical gap increased in the presence of surfactant and was recorded in the range of 2.7-2.8 eV for these samples. The photocatalytic properties of the samples were also investigated in Congo red at a concentration of 10 ppm. The results showed that ferrite bismuth made in the presence of sodium dodecyl sulfate had the most damage.
 

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In this research, the bismuth ferrite (BiFeO₃) nanostructure doped with Cu was prepared by a sol-gel method at a temperature of 650 ºC in a period of 60 minutes. First, bismuth ferrite nanoparticles are provided, then its doping with Cu (BiFe_1-yCu_yO₃) with y = 0.0, 0.05, 0.10 ,0.15 ,0.20, 0.25, and 0.30 has been done.  The structural properties of the samples have been characterized using the XRD, FESEM, FT-IR, and EDX. Investigations of the structural properties showed that as increasing Cu, the content of ferrite bismuth phase decreases and the secondary phases such as Bi₂O₃ ، Bi₂CuO₄ and Bi₂Fe₄O₉ have increased. The magnetic and dielectric properties of the samples using the analyses of VSM, and LCR meter have been investigated. Investigations of the magnetic properties showed that as increasing Cu, the magnetic properties of the samples improved. The dielectric constant and the dielectric loss of the samples decrease with increasing frequency, which indicates the natural dielectric behavior of bismuth ferrite.

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Abstract
 This research focuses on the fabrication and investigation of the structural and magnetic properties of magnetic oxide nanostructures of a novel Ni-Fe-Pb-Co alloy synthesized by the sol-gel method under argon gas. In this method, nickel nitrate, iron nitrate, lead nitrate and cobalt nitrate were used as precursor materials and citric acid as a chelating agent. The structural properties were investigated using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Fourier transform infrared spectroscopy (FT-IR) was used to analyze the chemical bonding of the substance. Also, the thermal stability of the compound was evaluated through thermal gravimetric analysis (TGA). The magnetic properties were determined using a vibrating sample magnetometer (VSM). The results showed that adding cobalt up to a concentration of 0.5 to the Ni-Fe-Pb system increased the saturation magnetization. XRD analysis of the samples showed the formation of a multi-component oxide. FESEM images show uniform particle distribution with a tendency for agglomeration at a temperature of 900 ℃. The Curie temperature of the magnetic oxide nanostructures of Ni-Fe_0.5-Co_0.5-Pb composition synthesized at 900 ℃ was measured using a Faraday balance and its value is 771 K.