Micro-Raman investigation of nanosized zinc ferrite: effect of crystallite size and fluence of irradiation

Zinc ferrite nanoparticles of different sizes ranging from 12 to 62 nm were synthesized by using the nitrate route. These nanoparticles were irradiated by a 100 MeV oxygen beam at two fluences: 1 x 10(13) and 5 x 10(13) ions/cm(2). It was observed that modes corresponding to cubic spinel phase were retained after the irradiation in all the systems. The variation in the parameters of various modes follows phonon confinement, while this effect seems to violate in irradiated specimen. It was found that the irradiation-induced changes in the modes F-2g(2) and F-2g(3) depend on whether the crystallite size of the pristine sample is less than, equal to or greater than the phonon confinement length, while this length is not dominant for the irradiation-induced changes in the mode A(1g). The changes in various parameters of the modes are attributed to the combined effect of the restructuring of the chemical species and ion-induced defects. Copyright (c) 2011 John Wiley & Sons, Ltd.