High temperature stability and low dielectric loss in colossal permittivity TiO2 based ceramics co-doped with Ag+ and Mo6+

In this work, dense (Ag2/5Mo3/5)(x)Ti1-xO2 ceramics (AMTOx) were successfully prepared by a conventional solid state method. The dielectric properties of AMTOx ceramics were systematically investigated. Good dielectric properties with superior temperature stability were realized in AMTOx ceramics. Encouragingly, the AMTO(0)(.0125) ceramics obtained a giant permittivity of similar to 20604 and a dielectric loss of similar to 0.045 at 1 kHz, while being able to satisfy with the requirement of application temperature of Z9R capacitor. Moreover, two kinds of dielectric relaxation behavior in low and high temperature region can be interpreted by the interface polarization, and ionization or displacement of oxygen vacancies, respectively. The data of complex impedance combined with XPS results further proved that internal barrier layer capacitor (IBLC) effect is the dominant mechanism of colossal permittivity in AMTOx ceramics.