Effect of Zn Concentration on Microstructural, Optical, and Hyperfine Properties of Nanocrystalline α-Fe2O3

Efforts have been made to prepare nanocomposites of α-Fe2O3-ZnO by wet chemical route with varying concentrations of the precursors. The microstructural properties of the samples are investigated by powder X-ray diffractometry (PXRD) and Transmission electron microscopy. Initial concentration of Zn ions (up to 20 at%) leads to the formation of nanocomposites of α-Fe2O3 and ZnO. Evolution of ZnFe2O4 phase is detected by the substitution of higher concentration of Zn2+ (30 at%) in the sample. The average size of the nanoparticles remains in the range of 22–27 nm as obtained from XRD data. The results obtained from electron microscopic studies are also close to these values. Photoluminescence measurement shows the excitonic peak of ZnO around 390 nm which gets strengthened with Zn addition. FTIR spectra show the metal–oxygen band below 700 cm−1. Room temperature Mössbauer studies of the samples show the transition of iron oxide form antiferromagnetic state to paramagnetic state with increasing concentration of Zn2+. Sharp quenching of hyperfine field with Zn concentration is observed as the Hint value reduced to zero from 51 T.