Phase transformations in radiolytically formed manganese nano-oxide

Abstract Nano-crystalline oxides of manganese prepared from the radiolysis of aqueous permanganic acid solution at ambient conditions showed structural and compositional changes with variation in absorbed gamma dose. The radiolytically formed nano-oxide was transformed into different micro-structures, phases, shapes and sizes with radiation. This variation was probed using X-ray powder diffraction (XRD), laser Raman spectroscopy (LRS) and transmission electron microscopy (TEM). At lower doses formation of a mixture of nano-oxides of Mn(OH)2, λ-MnO2 was detected from XRD analysis. This nano-oxide mixture changed to stable Mn3O4 at higher doses. The maximum crystallite size was observed to be ~15 nm. LRS results also supported this inference. This paper presents the detailed study on the phase transitions of the radiolytically formed nano-manganese oxides and the possibility of its use as radiation marker for predicting radiation response.