CaCu_3Ti_4O_(12)/In_(0.05)Nb_(0.05)Ti_(0.90)O_(12) composite ceramics: An effectively improved method to reduce the dielectric loss tangent and retain high dielectric permittivity

摘要

CaCu3Ti4O12/In0.05Nb0.05Ti0.90O12 (CCTO/INTO) composite ceramics with volume fraction ratios of 0.9/0.1 (10 % INTO) and 0.8/0.2 (20 % INTO) were prepared via a solid-state reaction method. XRD results indicated the mixed CaCu3Ti4O12 and TiO2 phases in the CCTO/INTO composite ceramics. The lattice parameter of the CCTO phase increased as the INTO composition increased, indicating the entry of some Nb5+ and/or In3+ ions into the CCTO lattice structure. The mean grain size of the CCTO/INTO composite ceramics was smaller than that of the CCTO ceramic, demonstrating that the grain boundary mobility of the CCTO phase was decreased by the INTO particles. Improved dielectric properties were achieved with a low dielectric loss tangent (0.029-0.046) in the CCTO/INTO composite ceramics, while high dielectric permittivities (5.0 x 10(3)-8.6 x 10(3)) were achieved. Nonlinear J-E behavior was demonstrated in the all-ceramic samples. The dielectric and nonlinear properties of the CCTO and CCTO/INTO composite ceramics originated from an internal barrier layer capacitor effect.