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Effects of Ce-Co Substitution on Magnetic and Dielectric Properties of Barium Hexaferrite Nanoparticles Synthetized by Sol-Gel Auto-Combustion Route

Lellahgani, Zahra | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 44981 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Nemati, Ali
  7. Abstract:
  8. In this study, the substituted barium hexaferrite nanoparticles with general formula Ba1-xCexFe12-xCoxO19 (x = 0, 0.1, 0.2 and 0.3) were prepared by the sol-gel auto combustion method. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), Mossbauer spectroscopy (MS), vibrating sample magnetometer (VSM) and performing network analyzer (PNA) were employed to investigation of structural, magnetic, dielectric and microwave properties of barium hexaferrite nanoparticles. Moreover, differential scanning calorimetry (DSC) were performed to observe the formation mechanism of barium hexaferrite. DSC studies showed that barium hexaferrite nanoparticles form from maghemite and barium monoferrite without the formation of hematite. XRD and FTIR studies showed that hexaferrite phase were obtained for all samples, but not all samples have a single hexaferrite phase, a second phase corresponding to barium monoferrite was also observed to form with increasing Ce-Co substitution. According to the FE-SEM micrographs, the particle size of barium ferrite powders were under 100 nm. Mossbauer spectra and VSM results revealed that Co ions preferentially occupy into the tetrahedral iron crystallographic sites, and increasing the x from 0 to 0.2 caused to increase the saturation magnetization from 41emu/g to 46emu/g, and increasing the x from 0 to 0.3 caused to decrease coercivity from 5500Oe to 4300Oe. The network analyzer results showed that the dielectric constant and dielectric loss decreased with increasing Ce-Co substitution
  9. Keywords:
  10. Nanoparticles ; Dielectric Constant ; Barium Hexaferrite ; Sol-Gel Autocombustion Method ; Saturation Magnetization ; Coercivity Force

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