Low loss giant dielectric and electrical transport behavior of KxTiyNi1−x−yO system

The KxTiyNi1−x−yO system in the series AxTiyNi1−x−yO (A=Li, K, Na; x=0.05–0.30, y=0.02) shows the highest dielectric constant ε′∼105 and lowest loss. The high ε′ value is attributed to microstructures, which form boundary layer capacitors. Electrical conductivity in these materials follows small polaron hopping mechanism in the nonadiabatic regime. Unlike LixTiyNi1−x−yO and NaxTiyNi1−x−yO (NTNO), KxTiyNi1−x−yO (KTNO) exhibits an anomaly around Tp∼430K. Tp shifts to the lower temperature range with increasing K content which is related to the higher ionic radius of K.