Study of vibrational modes of MeV Ni ion implanted MgO crystal

Abstract

The control over various vacancy and substitutional defects by ion implantation provides many interesting properties for the modulation of materials. In this report, we studied the effect of defects and anionic vacancies produced by MeV Ni ion implanted single crystal MgO on different vibrational active modes. The breathing mode of D bands is observed for most of the Raman peaks, and simultaneously, the overlapping of D and G bands is confirmed from Raman spectra. The Fourier Transform Infrared spectra identified the stretching and bending vibrations of Mg, O, and Ni atoms and compared them with pristine. The presence of atmospheric constituents and their role in affecting the vibrational modes are well justified. The phonon band and density of states calculation in the framework of density functional theory confirms the presence of T1u and T2u Raman active mode that arises due to vibration from different vacancy and substitutional defect associated in MgO structures, agrees well with experimental results. The tunable anionic vacancies produced in MgO by ion implantation can be beneficial to form the filament in valance charge memory-based resistive random-access memory (RRAM).