Preparation of core/shell structured NiO-based ceramics and their dielectric properties

High-permittivity dielectric core/shell structured Li-0.01 SixNi0.99-xO ceramics (abbreviated as LSNO) have been successfully prepared. Analyses of the ceramic microstructure and composition indicate that the dopants of SiO2 are mainly dispersed into the grain boundaries and exist as the insulating Ni2SiO4 phase. All the LSNO ceramic samples exhibit high permittivity, and the permittivity reaches about 1.2 x 10(4) for the LSNO-1 sample. The concentration of Si has a remarkable effect on the dielectric properties of the LSNO ceramics. The origin of the high permittivity observed in these LSNO ceramics is attributed to the Maxwell-Wagner polarization mechanism and a thermally activated mechanism.