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

The KxTiyNi1-x-yO system in the series A(x)Ti(y)Ni(1-x-y)O (A=Li, K, Na; x=0.05-0.30, y=0.02) shows the highest dielectric constant epsilon'similar to 10(5) and lowest loss. The high epsilon(') 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 T-p similar to 430 K. T-p shifts to the lower temperature range with increasing K content which is related to the higher ionic radius of K. (c) 2006 American Institute of Physics.