Angle Dependent X-Ray Absorption Spectroscopy for Investigation of Irradiation Induced Effects in MgO Single Crystals

Abstract

Present work investigated the ion irradiation-induced effects in MgO single crystals using angle dependent X-ray absorption spectroscopy. MgO single crystals were irradiated using 100 MeV O7+ ions at fluences of 1 x 1011, 1 x 1012, and 1 x 1013 ions/cm2. X-ray diffraction study showed the presence of the same crystalline structure in the pristine and irradiated counterparts. Variation of X-ray intensities with ion fluence exhibited onsets of crystalline disorder, which were supported by the variation of lattice parameter with fluence. This behavior is further confirmed by the behavior of the local atomic distortion parameter estimated from Mg K-edge near edge X-ray absorption fine structure (NEXAFS) measurements. Further, angle dependent NEXAFS measurements revealed the onsets of slight distortion in atomic structure. These effects were attributed to the dominant electronic excitation in the ion irradiated MgO single crystals.