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Evangelin Hutamaningtyas,Utari,Suharyana,Budi Purnama,Agung Tri Wijayanta 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.4
The effects of the synthesis temperature on the crystalline structure and the magnetic properties of cobalt ferrite (CoFe2O4) nanoparticles prepared via coprecipitation are discussed. The synthesis was conducted at temperatures of 75 C, 85 C and 95 C. Fourier transform infrared spectroscopy characterization related to a stretching vibration at a wavenumber of 590 cm−1 indicated the formation of a CoFe2O4 metal oxide. In addition, powder X ray diffraction (XRD) characterization proved that the metal oxide was CoFe2O4. Crystallite sizes calculated using the Scherer formula at the strongest peak of the XRD spectra of the samples synthesized at 75 C, 85 C and 95C were 32 nm, 43 nm and 50.4 nm, respectively. Finally, the results of the vibrating sample magnetometer characterization showed that the saturation magnetization decreased with increasing synthesis temperature, which is related to the dominant preference of Co2+ over Fe3+ cations at the octahedral sites.
Budi Purnama,Anisa Khoiriah,Suharyana 한국자기학회 2018 Journal of Magnetics Vol.23 No.1
The crystal structure and magnetic properties of aluminium-substituted cobalt-ferrite nanoparticles synthesised by the co-precipitation are reported in this study. The single phase nanoparticles are obtained. Magnetic property Changes in these properties are clarified mainly by changes in parameters such as the crystalline constant, crystallite size and crystalline density. An increase of saturated magnetisation with annealing temperature is also observed. Results for the change in saturated magnetization at several elevated temperatures indicate that the available non-magnetic aluminium ions support redistribution of cation-trivalent Fe<SUP>3+</SUP> during the annealing process at octahedral sites.
Budi Purnama,Rafika Rahmawati,Agung Tri Wijayanta,Suharyana 한국자기학회 2015 Journal of Magnetics Vol.20 No.3
Modifications in the structural and magnetic properties of co-precipitated cobalt ferrite nanoparticles can be accomplished by varying the annealing time periods during the synthetic process. Experimental results show that high-purity cobalt ferrite nanoparticles are obtained using a co-precipitation process. The dependence of the crystallite sizes on the annealing time was successfully demonstrated using XRD and SEM. Finally, vibrating sample magnetometer analyses show that the magnetic properties of the cobalt ferrite nanoparticles depend on their relative particle sizes.