A Novel Route to Greatly Enhanced Dielectric Permittivity with Reduce Loss Tangent in CaCu_3−xZn_xTi₄O₁₂/CaTiO₃ Composites

Abstract

Dielectric and nonlinear properties of a binary compound derived from Ca2Cu2Ti4O12 were greatly improved by doping with Zn2+ to deliberately create CaCu3–xZnxTi4O12/CaTiO3 composites. Ca2Cu1.8Zn0.2Ti4O12 composition can exhibit an enhanced ε′, ~6,513, with a strong reduction in tanδ to ~0.015 (at 1 kHz). The nonlinear coefficient and breakdown field strength were significantly enhanced. The dielectric and nonlinear properties were described based on the effect of Zn2+ substitution on electrical response of internal interfaces.

Influences of Sr2+ Doping on Microstructure, Giant Dielectric Behavior, and Non-Ohmic Properties of CaCu3Ti4O12/CaTiO3 Ceramic Composites

“…No possible impurity phase, e.g., CuO or SrTiO 3 , was observed. This observation is similar to those reported in the literature for the CCTO/CTO composites [ 20 , 21 , 26 , 28 , 32 ], which comprised of ~66.7 mol% CCTO and ~33.3 mol% CTO [ 18 , 28 , 29 ]. The nominal composition of CCTO/CTO can be written as Ca(Cu 2 Ca)Ti 4 O 12 , which is similar to that of CCTO.…”

Grain boundary engineering that induces ultrahigh permittivity and decreased dielectric loss in CdCu3Ti4O12 ceramics

“…The details of the results are provided in Table . The unknown phases in the grain boundaries of the CdCTO‐04Zn ceramics are Cu/Zn‐enriched phases, while that in the CdCTO ceramics is a Cu‐enriched phase …”

“…The unknown phases in the grain boundaries of the CdCTO-04Zn ceramics are Cu/Zn-enriched phases, while that in the CdCTO ceramics is a Cu-enriched phase. [26][27][28][29][30][31][32][33][34] The frequency-dependent dielectric behavior of the CdCu 3−x Zn x Ti 4 O 12 ceramics is shown in Figure 4A; the inset shows an enlarged view of the frequency-dependent (40-10 4 Hz) dielectric loss tangent. The dielectric permittivity maintains a high value above 2.0 × 10 4 and seems to be frequency independent when the measured frequency is below 10 5 Hz, while a sharp decrease to ~100 occurs when the frequency reaches 10 7~1 0 8 Hz.…”

“…Because it has a relatively high electrical resistance, ZnO has often been selected as a dopant to enhance the resistance of dielectric materials . The mechanism lies in the fact that zinc doping tends to induce a high‐resistance local ZnO environment that replaces the low‐resistance CuO environment in the host lattice . Therefore, in this paper, we chose Zn 2+ ions to substitute for Cu 2+ ions in CdCTO ceramics to improve the grain boundary resistance to achieve a reduced dielectric loss tangent.…”

“…[23][24][25][26][27][28] The mechanism lies in the fact that zinc doping tends to induce a high-resistance local ZnO environment that replaces the low-resistance CuO environment in the host lattice. [27][28][29] Therefore, in this paper, we chose Zn 2+ ions to substitute for Cu 2+ ions in CdCTO ceramics to improve the grain boundary resistance to achieve a reduced dielectric loss tangent. The effects of Zn 2+ doping on the phase structure, microstructure and dielectric properties were examined in detail.…”