Effects of gamma irradiation on structural and optical properties of nanocrystalline Mn0.4Zn0.6SmxGdyFe2-(x+y)O4
K. Praveena1*, Hsiao-Wen Chen1, Song-Hsun Huang1, Hsiang-Lin Liu1
1Department of Physics, National Taiwan Normal University, Taipei, Taiwan
* presenting author:Praveena Kuruva, email:praveena@ntnu.edu.tw
Samarium and Gadolinium doped Manganese zinc ferrite nanocrystalline powders with general formula Mn0.4Zn0.4SmxGdyFe2-(x+y)O4 (x = 0.01, 0.02, 0.03, 0.04 and 0.05) were synthesized through novel combustion route and calcined at 600°C. The X-ray diffraction (XRD) patterns were measured for the prepared samples to confirm the existence of monophasic spinel phase structure. The crystallite size was estimated to be within the range 50–60 nm. To study the radiation effects on the structural and optical properties, a representative group of the investigated samples were irradiated by crays of 60Co source with a dose of 50 kGy. The XRD spectra were recorded on the irradiated samples and compared with that of the un-irradiated samples to estimate changes in the structure. The obtained results showed that the crystallite size increased by a factor of 10–16% after gamma irradiation. The lattice parameter also was increased due to the conversion of Fe3+ (0.64 Å) to Fe2+ (0.76 Å) and because of codoping of Sm3+-Gd3+. The room temperature Raman scattering and spectroscopic ellipsometry measurements were performed on before and after gamma irradiation. According to group theory, five Raman active phonon modes were observed and fitted using Lorentzian equation. The optical constants (n and k) and their doping behaviour will be discussed in detailed.

Keywords: Ferrites, Manganese zinc ferrites, Sol-gel synthesis, Raman spectroscopy, Spectroscopic elipsometry