Effect of cobalt-doping on the dielectric properties and densification temperature of Li2MgSiO4 ceramic: Calculation and experiment

Abstract

The first principle calculation was conducted to predict the effect of Co2+ ion substitution on the crystal structure, electron density, formation energy and vibration properties of Li2MgSiO4 ceramic. All the samples were synthesised through the solid-state reaction method. Variations in sintering and dielectric properties were analysed through X-ray diffraction, scanning electron microscopy, network analysis, Raman spectrometry, thermomechanical analysis and simultaneous thermal analysis. Bond length, bond population and electron distribution in a MgO4 tetrahedron were modified due to the substitution of Mg2+ ion by Co2+ ion. The densification temperature was lowered from 1250 °C to 1050 °C with the addition of 5% (molar ratio) Co2+ ions. The sintering window was put forward slightly, and the vibration property was changed. The densification level and microwave dielectric properties were improved accordingly at following conditions: εr = 5.75, Q × f = 26,500 GHz at 16 GHz, τf = −9.4 ppm/°C and relative density = 95.2%. The dielectric and sintering properties of Li2MgSiO4 ceramic could be enhanced with the substitution of Mg2+ ion by Co2+ ion.