Transmission electron microscope studies on Li-doped MgO

Abstract

Transmission electron microscope investigations of as-grown Li-doped MgO have revealed the presence of precipitates with an average size of 220 A. Detailed micro-diffraction studies and moiré pattern analyses have identified these precipitates as Li₂O with the cubic fluorite structure. Exposures of Li-doped MgO crystals either to high temperatures in air for 10 min followed by quenching or to a large dose of ionizing radiation at ambient temperature leads to a reduction in the precipitate size. These results lend support to our previous conjecture from optical and magnetic resonance studies that localized lithium-rich environments are responsible for the stable [Li]⁰ centres and that the source of these lithium ions are the precipitates.