Effects of rare-earth oxides on temperature stability of acceptor-doped BaTiO3

The effects of rare-earth oxides (Yb2O3, Ho2O3, Er2O3) on the temperature stability of acceptor doped BaTiO3 dielectrics were studied. The samples doped with 1 mol % rare-earth oxides exhibited the highest dielectric constants. Substantial reductions in grain size were observed in the specimens with 1 mol % rare-earth oxides (similar to 0.6 mu m) compared with the nondoped specimens (similar to 1.5 mu m). As the rare-earth oxide content was increased, the Curie point progressively moved to higher temperatures. The addition of rare-earth oxides improved the temperature dependence of the dielectric constants of the acceptor-doped BaTiO3-rare-earth oxide systems over the whole temperature range studied (-55 to 150 degrees C), and the temperature coefficient of capacitance(TCC) curves satisfied the X8R requirements for > 2 mol % Yb2O3 and > 3 mol % Er,03 or Ho2O3.