Size distribution of magnetic iron oxide nanoparticles using Warren-Averbach XRD analysis

摘要

We use the Fourier transform based Warren-Averbach (WA) analysis to separate the contributions of X-ray diffraction (XRD) profile broadening due to crystallite size and microstrain for magnetic iron oxide nanoparticles. The profile shape of the column length distribution, obtained from WA analysis, is used to analyze the shape of the magnetic iron oxide nanoparticles. From the column length distribution, the crystallite size and its distribution are estimated for these nanoparticles which are compared with size distribution obtained from dynamic light scattering measurements. The crystallite size and size distribution of crystallites obtained from WA analysis are explained based on the experimental parameters employed in preparation of these magnetic iron oxide nanoparticles. The variation of volume weighted diameter (D _v, from WA analysis) with saturation magnetization (M _s) fits well to a core shell model wherein it is known that M _s=M _(bulk)(1-6g/ D _v) with M _(bulk) as bulk magnetization of iron oxide and g as magnetic shell disorder thickness.