Electrical responses in high permittivity dielectric (Li, Fe)-doped NiO ceramics

摘要

Electrical properties of giant-permittivity core/shell structured Li_(0.005)Fe_xNi_(0.95-x)O (LFNO) are studied as functions of frequency, temperature, and dc bias. Three electrical responses of depletion surface (DS), grain boundary (GB), and bulk grain are detected in the LFNO ceramics. The DS and GB effects can be separated by removing the surface samples, whereas the grain effect is extracted by applying dc bias. It is found that the interfacial polarizations at the DSs and GBs are suppressed by applied voltages. Our results suggest that the polarization relaxation in the LFNO ceramics is closely related to the electrical response inside the grains.