Improvement of insulation reliability of BaTiO_3-based ceramics using mixed conductive electrode

摘要

The insulation degradation of BaTiO_3-based ceramics under direct-current field is caused by the migration of oxygen vacancies. To improve the reliability of BaTiO_3-based ceramic capacitors, conventional approaches are focusing on dielectrics, mainly working on suppressing the total amount of oxygen vacancies towards the cathode. In this study, we newly focus NOT on the dielectrics but on the electrodes, and tried to improve the reliability of BaTiO_3-based ceramics by suppressing the segregation of migrated oxygen vacancies. La_(0.8)Sr_(0.2)MnO_3 (LSM) is a mixed ionic-electronic conductor that generates oxide ions from gas-phase oxygen. We expected that LSM would compensate for migrated oxygen vacancies when using it as the cathode of a BaTiO_3-based ceramic capacitor. The results of our highly-accelerated life tests indicate that the reliability of BaTiO_3-based ceramics improved when LSM porous ceramics was used only as the cathode, (NOT the anode).