The Influence of La_2O_3 Additive on the Dielectric Properties of Ba_(0.6)Sr_(0.4)TiO_3-MgO Bulk Ceramics

摘要

The influence of La_2O_3-doping on the dielec- tric properties of Ba_(0.6)Sr_(0.4)TiO_3-6wt%MgO was studied. With the increase of La_2O_3-doping content, the space between adjacent parallel crystal planes of BST-MgO composite first became larger, then smaller. Proper quantity of La_2O_3 could ensure moderate dielectric constant and reduce the dielectric loss of BST-MgO composite at high frequency, but excess quantity of La_2O_3 would lower dielectric constant. When the La_2O_3-doping content was 0.2wt%, the dielectric constant and loss of BST-MgO composite were equal to 93.2 and 0.005 (1MHz), respectively. And the dielectric constant tunability could be obtained to 12.1% (21kV/cm).