Abstract
BaTiO 3 ceramics are doped with SiO 2 , Nb 2 O 5 , Dy 2 O 3 and LiF and then sintered in various a tomspheres. Electron paramagnetic resonance (EPR) spectroscope is employed to study the possible defects in the BaTiO 3 grain boundary barrier layer (GBBL) capacitors. EPR results suggest the existence of V Ba ' defects. V Ba ' The enhanced EPR signal at 140°C for undoped BaTiO 3 is due to the increase of V Ba resulting from tetragonal to cubic phase transformation. Neutral V Ba and doubly ionized V ″ Ba vacancies may be present as a result of electron transfer with V Ba . It is argued that diffusion of metal ions affects the oxidation of the grain boundary layer of GBBL BaTiO 3 , capacitors. © 1990.