Opto-electric and physio-chemical changes in oxygen ion irradiated natural Vermiculite mineral

Highlights: • Natural Vermiculite was irradiated with 80 MeV of oxygen ion for the first time. • Cody model was employed to calculate structural disorder using optical spectra. • Dielectric properties were significantly enhanced by the irradiation process. • FTIR spectra show the disappearance of chemisorbed CO₂ band at higher fluences. • Vermiculite was found as a suitable candidate for radiation dosimetry applications. - Abstract: The influence of 80 MeV O⁶⁺ ion on Vermiculite mineral in terms of its optical, dielectric, structural, chemical, and thermoluminescence (TL) properties have been reported in this paper for the first time. The structural disorder was computed from Urbach energy using Cody model, and was applied to reveal the variation of optical band gap with ion fluence. The ac conductivity (σ_ac) in both pristine and irradiated samples was found to obey Jonscher's power law. The mean crystallite size, micro strain and dislocation density were estimated from the analysis of X-Ray Diffraction pattern. The results of optical and dielectric parameters were found to be corroborated with structural changes of pristine and irradiated samples. FTIR spectroscopy of the samples reveals the broadening of bands and the decrease in overall intensity of the transmittance with the increase in ion fluence. Thermoluminescence studies were also performed to explore the dosimetric aspects of vermiculite. A prominent TL peak was observed around 148 °C to make Vermiculite a good dosimeter for eminent uses in radiation rich environs.