Enhancement of ionic conductivity in Li₂O–SiO₂ glass in nanodimensions grown within pellets of ZnO nanorods and magnetodielectric properties of these nanocomposites

Abstract

23Li₂O·77SiO₂ glass with nanodimensions was grown within the pores of a pellet formed by ZnO nanorods of a diameter of 70 nm and lengths varying from 80 nm to 270 nm. The resistivity of the nanoglass was less than that of its bulk counterpart by more than three orders of magnitude. The activation energy was found to be 35% lower than that of the bulk glass. This was ascribed to an increase in free volume in the nanodimensional glass. The ac conductivity variation at high frequency showed an exponent of 0.5 indicating two dimensional movements of lithium ions in the nanoglass. Nanocomposites of lithia–silica nanoglass and CuO nanoparticles showed magnetodielectric property with dielectric permittivity at 500 kHz decreasing by 5.3% at 2 T. This was explained on the basis of space charge polarization and Hall Effect. Nanocomposites of lithia–silica nanoglass and ZnO nanorods exhibited a giant magnetodielectric effect with the dielectric permittivity increasing by 20% to 99% at 2 T depending on the measuring frequency. This was also ascribed to space charge polarization with the ZnO nanophase showing a negative magnetoresistance.