Dielectric and nonlinear electrical behaviors of La-doped CaCu3Ti4O12 ceramics

Abstract

We prepared La doped of CaCu3Ti4O12 ceramics by a solid-state sintering process and observed nonlinear electrical varistor and high dielectric behaviors. Phase composition analyses show that the La can substitute on the Ca sites completely, and have no influence on the phase composition. The impedance spectroscopy at room temperature indicates that the La doping can maintain the dielectric permittivity of CaCu3Ti4O12 (∼104). The relationships between electrical current density versus applied electrical field show that these ceramic samples exhibit nonlinear varistor characteristics, which should be ascribed to the existing potential barrier height at the grain boundary.

Grain size effect on the giant dielectric and nonlinear electrical behaviors of Bi1/2Na1/2Cu3Ti4O12 ceramics

“…In the whole frequency range, the dielectric constant keeps at a giant value between ∼5 × 10 3 and ∼4.5 × 10 5 . With increasing grain size, the dielectric constant increases gradually, which is in accordance with the results of CCTO ceramics [8][9][10][11]13]. The dielectric constants for BNCTO-1, BNCTO-2, BNCTO-3, and BNCTO-4 samples at 1 kHz are 14110, 20004, 27694, and 36183, respectively.…”

“…The static dielectric constant of CCTO is about 10 4 around radio frequency at room temperature, which is also thermal stable between 100 and 600 K [1][2][3]. A different effect, the nonlinear electrical behavior of pure and doped CCTO, has also been studied by many researchers [6][7][8][9][10].…”

High Breakdown Field CaCu3Ti4O12 Ceramics: Roles of the Secondary Phase and of Sr Doping

“…A similar phenomenon is also observed in the CCTO/MgTiO3 [9] and CCTO/CaTiO3 [21] composite ceramics, and it has been attributed to the missing charge carriers. In addition, according to the formula of stored energy U = (ε′Eb 2 )/2, the maximum U calculated for CCTO-0.5 CuAl2O4 and 0.4SCTO-0.6CCTO samples are correspondingly 44.1 and 50.9 kJ·m −3 in this work, which is a great improvement over that of CCTO ceramics of 2-7 kJ·m −3 in previous works [1,3,20,21]. Permittivity and dielectric loss at room temperature of CCTO, CCTO-0.5CuAl 2 O 4 , and 0.4SCTO-0.6CCTO ceramics are presented in Figure 4.…”

“…Results of the breakdown field and the nonlinear coefficient are shown in Figure 3b. It can be found that the CCTO-0.5CuAl 2 O 4 and 0.4SCTO-0.6CCTO samples show an extremely high breakdown electric field E b of about 20 kV·cm −1 , which is almost 10 times of former works in both pure CCTO ceramics [3,20] Energies 2017, 10, 1031 5 of 10 and CCTO-based composite ceramics [9]. The breakdown field of 0.4SCTO-0.6CCTO samples sintering at 1000 • C for 5 h even reaches 23.8 kV·cm −1 and that of CCTO-0.5CuAl 2 O 4 samples also achieves 21 kV·cm −1 , which are the highest values ever reported.…”

The Effect of Sintering Conditions on the Microstructure and Electrical Properties of Pb(Zr0.52Ti0.48)O3 Ceramic

“…Cheng et al (2009) investigated whether the dielectric constant of ceramic materials were highly dependent on the processing conditions such as milling time, sintering temperature and duration of the sintering. The dielectric constant was reported to be 2000 to 80000 by varying the sintering condition, and ascribed to giant barrier layer effects at grain boundary (Fang & Chung, 2011;Ramesh, Tan, Amiriyan, & Teng, 2011;Sivakumar, Ramesh, Chin, Tan, & Teng, 2011).…”