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Abstract
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In present study, magnetic nanoparticles of barium hexaferrite, strontium hexaferrite and barium strontium hexaferrite were synthesized by co-precipitation method. Synthesis parameters such as starting materials, temperature and solvents were chosen constant, so the product's properties were fully compared. In order to synthesize barium hexaferrite, chloride salts of iron and barium with a Fe/Ba molar ratio of 11 and to prepare strontium hexaferrite, chloride salts of iron and strontium with the Fe/Sr ratio of 12 were utilized, while, to synthesize barium-strontium hexaferrite, same chloride salts with the Fe/Ba, Fe/Sr ratios of 24 were used. A mixture of water and ethanol with a ratio of 1 to 3 was utilized as the solvent and NaOH as a precipitant agent with an OH−/Cl− ratio equal to 2 at room temperature was applied. Co-precipitated precursor samples were dried at 80°C for 24 hours and then they were annealed at 950°C for 1 hour to diffuse Ba2+ and Sr2+ into iron oxide and subsequently to form hexaferrite phases. Powder's properties were characterized by means of X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). XRD technique was applied to identify the formed phases and to study crystallite sizes. The magnetic properties of the powders determined by the VSM technique indicated that the barium strontium hexaferrite was superior.
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