Field enhanced bulk conductivity of acceptor-doped BaTi1−xCaxO3−x ceramics

Abstract

The electrical properties of Ca-doped BaTiO3 are very different when Ca substitutes onto Ba or Ti sites. The p-type semiconductivity of Ti-substituted ceramics increases reversibly by one to two orders of magnitude under a dc-bias voltage of ≤100 V cm−1, whereas Ba-substituted ceramics show little sensitivity to a dc bias. This increase in BaTi1−xCaxO3−x, studied over the temperature range 150–600 °C, is independent of electrode material and atmosphere and is attributed to ionization of underbonded O2− ions adjacent to acceptor-doped Ca2+ ions.