Switchable phase transition of crystalline to amorphous state of potassium nitrate single crystal

Abstract

High-pressure materials science always has a special benchmark in the current research areas wherein dynamic shock waves have also made striking inroads on a par with high-pressure experiments in solids and have marked a tremendous impact in expanding the materials science research both in academics as well as applications point of view. In this context, we report and demonstrate the switchable phase transition of crystalline to the amorphous state of potassium nitrate (KNO3) single crystal at shocked conditions such that the observed results of phase transition have been evaluated by X-ray diffraction (XRD), Raman and optical spectroscopic as well as Field –emission scanning electron microscopic (FE-SEM) techniques. The observed phase transition sequence is crystal-crystal-crystal-amorphous-crystal-glassy crystalline nature that is exhibited by KNO3 crystals with respect to 0, 1, 2, 3, 4, and 5 shock pulses. The formation of amorphous KNO3 is because of the rotational disorder of the oxy-anions of the NO3 units and the positional disorder of potassium ions. Strikingly, to date, it could be the first report of amorphization on KNO3 considering both the static pressure and temperature experiments. Due to the ability of potential switching between crystalline and amorphous states, the title material is a good fit for the applications of optical data storage and molecular switching.