Improved grain boundary resistance inducing decreased dielectric loss and colossal permittivity in Y2/3Cu3Ti4O12 ceramics

How to simultaneously realize a low loss and a large permittivity has always been a thorny problem in the research of ACu 3 Ti 4 O 12 (ACTO) family perovskite-like materials. In this work, we successfully synthesized Mg-doped Y 2/3 Cu 3 Ti 4 O 12 (YCTO) ceramics with low dielectric loss and large permittivity via a mixed oxides technique. With a Mg doping level of 0.05, a Y 2/3 Mg 0.05 Cu 2.95 Ti 4 O 12 ceramic displayed a suppressed dielectric loss tangent of ∼0.027 and a larger dielectric constant of ∼12,370. Moreover, the breakdown field strength of Y 2/3 Mg 0.1 Cu 2.9 Ti 4 O 12 ceramics is up to 4.85 kV/cm. The improved dielectric properties of the produced ceramics were attributed to the enhanced grain boundary resistance upon Mg doping based on the data acquired from impedance and electric assessments. The findings presented in this work provide valuable insights on the simultaneous realization of a large permittivity and low dielectric loss in YCTO and other related dielectric ceramics. • A loss tangent of ∼0.027 and a colossal permittivity of ∼12,370 was realized simultaneously. • The improved dielectric properties were closely related to the increased grain boundary resistance. • The breakdown field strength of Y 2/3 Mg 0.1 Cu 2.9 Ti 4 O 12 ceramics is up to 4.85 kV/cm.