Fractal growth of single-crystal α-Fe2O3: From dendritic micro-pines to hexagonal micro-snowflakes

The fractal nanostructures of single-crystal α-Fe2O3 with micro-pine and micro-snowflake like morphologies have been synthesized via a hydrothermal route. The crystallinity, composition, purity, morphology and microstructure of the synthesized hematite were characterized by X-ray diffraction, Mössbauer spectrometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). A possible growth mechanism for these two kinds of fractal structures was proposed based on careful SEM and TEM observations. The role of the surfactant NP-9 in the conversion of the two kinds of fractal structures was discussed.