Particle size dependence of optical and defect parameters in mechanically milled Fe2O3
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Fe2O3 of particle sizes ranging from 120 to 20 nm has been prepared by the ball-milling process using different milling hour. X-ray diffraction technique and transmission electron microscopy have been used for determining the average particle sizes of the prepared samples. Direct optical band gap for the unmilled and the ball-milled samples has been calculated from the optical absorption data. A red shift in the band gap due to the reduction of particle size has been observed. The coincidence Doppler broadening of the electron positron annihilation γ-radiation spectroscopy has been employed to identify the nature of defects generated due to the ball-milling process.
KeywordsMilling Decrease Particle Size Core Electron Milled Sample Defect Parameter
M. Chakrabarti and M. Sutradhar gratefully acknowledge CSIR, Government of India, for providing financial assistance. A. Banerjee gratefully acknowledges Prof. S. K. Pradhan, Department of Physics, Burdwan University, for his valuable suggestions. The authors are thankful to Prof. G. N. Mukherjee, Department of Chemistry, University of Calcutta, for the optical measurement. The authors are also thankful to Mr. P. Ray, SINP, Kolkata, for the TEM measurement and A. Kar Mahapatra, SINP, Kolkata, for the XRD measurement.
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