Sol-gel 법을 이용한 Ba_(1-x)Eu_(x)TiO₃ ceramics의 유전 특성

Abstract

Rcently, many authors studied the effect of rare earth (RE) doping on the dielectric properties of BaTiO(BT). The Eu modification in BT was firstly studied by solid state reaction method even under high pressure. The alternative approach is needed for the Eu modification in BT, because the melting point of EuO is so high. The sol-gel method was more efficient for the homogeneous Eu substitution in the nano-sized BT, (Ba,Sr)TiO ceramics and even BT thin films. It is expected that the sol-gel method reduces the temperatures considerably for processing the Eu modified BT ceramics and enhances the homogeneous modification of Eu in the BT ceramics. In this study, BaEuTiO(x=0∼0.2) ceramics were prepared from the BET nano particles, where the sol-gel method were employed to Eu substitute homogeneously for Ba in the BT. With calcining and sintering the BET nano particles, the grain sizes of BET ceramics were measured to be about 0.1∼1.0m by scanning electron microscopy. The BET ceramics exhibited the ferroelectric D-E hysterysis. The Curie temperature shifted toward 70℃ for BET(x=0.1) ceramics and displayed the diffused phase transitions behaviors. It is considered that the Curie temperature of BET was lowered the incoporation of Eu ions, where Eu substituted for Ba in A sites of BaTiO.