A study on the phase transition and characteristics of rare earth elements doped BaTiO3

Non-reducible dielectric composition satisfying X8R specifications (−55 to 150°C, ±15%) for automotive applications was investigated in a BaTiO₃-MgCO₃-MnO₂-rare earth elements (La, Pr, Gd, Tb, Dy, Ho, Er, Yb, Lu) system. In the cases of Er, Yb, Lu-substituted samples, a transition of the Curie point shifted to a higher temperature was observed. The peak shift toward higher temperatures indicated that the tetragonal phase became more stable at the high temperature. The ionic radius of rare earth elements was found to be an important factor in controlling the temperature dependency of the dielectric properties. Especially, smaller ionic radii of rare earth elements such as Yb and Lu were effective dopants to meet the X8R temperature-capacitance characteristics.