27 مهر 1398
محمود ناصري

محمود ناصری

مرتبه علمی: دانشیار
نشانی:
تحصیلات: دکترای تخصصی / فیزیک-نانو
تلفن: 08132355404
دانشکده: علوم پایه

مشخصات پژوهش

عنوان
A comprehensive overview on the structure and comparison of magnetic properties of nanocrystalline synthesized by a thermal treatment method
نوع پژوهش مقاله چاپ شده
کلیدواژه‌ها
Nanostructures . Infraredspectroscopy . (Thermo-gravimetricanalysis(TGA . X-raydiffraction (Electronparamagneticresonance(EPR
سال
2014
مجله JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
پژوهشگران محمود ناصری

چکیده

This study reports the simple synthesis of MFe2O4 (where M=Zn, Mn and Co) nanostructures by a thermal treatment method, followed by calcination at various temperatures from 723 to 873 K. Poly(vinyl pyrrolidon) (PVP) was used as a capping agent to stabilize the particles and prevent them from agglomeration. The pyrolytic behaviors of the polymeric precursor were analyzed by use of simultaneous thermo-gravimetry analyses (TGA) and derivative thermo-gravimetry (DTG) analyses. The characterization studies were conducted by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Fourier transform infrared spectroscopy (FT-IR) confirmed the presence of metal oxide bands for all the calcined samples. Magnetic properties were demonstrated by a vibrating sample magnetometer (VSM), which displayed that the calcined samples exhibited different types of magnetic behavior. The present study also substantiated that magnetic properties of ferrite nanoparticles prepared by the thermal treatment method, from viewing microstructures of them, can be explained as the results of the two important factors: cation distribution and impurity phase of α-Fe2O3. These two factors are subcategory of the preparation method which is related to macrostructure of ferrite. Electron paramagnetic resonance (EPR) spectroscopy showed the existence of unpaired electrons ZnFe2O4 and MnFe2O4 nanoparticles while it did not exhibit resonance signal for CoFe2O4 nanoparticles.