Mg Defect Induced Ferromagnetic Ordering in Li-Doped MgO Nanostructures

Abstract

Magnesium deficient Li-doped MgO nanostructures were fabricated by hydrothermal method to investigate their structural, electronic, and magnetic properties. X-ray diffraction study confirms the single-phase crystallinity and changing the Li concentration (2%, 4% & 6%) in the host matrix of MgO induced strain and increased the crystallite size. Field-effect scanning electron microscopy images show the change in morphology from flakes to prismatic type nanostructures with the variation in Li content. The increase in Mg defects with an increase in Li doping, elucidated by X-ray photoelectron spectroscopy, would be the plausible reason for origin of d0 ferromagnetism and can be explained through (Li1+–VMg–Li1+) exchange interaction mechanism. Also, this increase in Mg defects leads to an increase in the value of saturation magnetization and grain size as well. Furthermore, electron paramagnetic resonance measurements explored the concepts of g-value and line width which are related with Mg defects and super exchange interaction of paramagnetic ions.