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

Abstract

Single phase Bi 1/2 Na 1/2 Cu 3 Ti 4 O 12 (BNCTO) ceramics with different grain sizes (1.4-4.3 µm) are prepared by a modified Pechini method to investigate their giant dielectric and nonlinear electrical behaviors. The results show that the giant dielectric and nonlinear electrical behaviors are strongly dependent on grain size. With the increment of grain size, the dielectric constant increases monotonically from 14110 (for 1.4 µm sample) to 36183 (for 4.3 µm sample) at 1 kHz, in accompaniment with the breakdown voltage reducing from 112.5 to 43.2 V/mm and the nonlinear coefficient reducing from 4.9 to 3.4. On the basis of the internal barrier layer capacitor (IBLC) model and the IBLC model of Schottky-type potential barrier, an interpretation of the grain size effect on the giant dielectric and nonlinear electrical behaviors is presented.

Synthesis, dielectric properties, and influences oxygen vacancies have on electrical properties of Na1/2Bi1/2Cu3Ti4O12 ceramics prepared by a urea combustion method

“…It is notable that e 0 of NBCTO ceramics decreased as the mean grain size increased. This is contrary to the study of Qiu et al [19].…”

“…These XRD patterns are similar to the XRD pattern of the CaCu 3 Ti 4 O 12 structure (JCPDS 75-2188). The overall XRD patterns are similar to NBCTO ceramics prepared using a conventional solid-state reaction method [26] and other chemical solution methods such as a modified Pechini method [19], sol-gel method [24], combustion method using glycine as a fuel [22], and a co-precipitation method [30]. Unfortunately, a single phase of these NBCTO powders was not obtained using these chemical routes or it was not reported.…”

“…CCTO exhibited very high dielectric permittivity (e 0 & 10 3 -10 5 ), depending on several factors including sintering time and temperature [3][4][5][6], electrode material [7,8], annealing treatment [9,10], stoichiometry of Ca, Ti, and Cu [1,11,12], and preparation method to produce CCTO powder [13,14]. Giant dielectric properties of related oxides in the family of ACu 3 Ti 4 O 12 compounds, where A = Bi 2/3 , La 2/3 , Y 2/3 , Na 1/2 Bi 1/2 , Na 1/2 La 1/2 , Na 1/2 Y 1/2 , and Na 1/3 Ca 1/3 Bi 1/3 , have also been observed [15][16][17][18][19][20][21][22][23][24][25][26][27]. Generally, CCTO and ACu 3 Ti 4 O 12 ceramics are synthesized via a solid-state reaction (SSR) method [15-18, 23, 26].…”

Effects of multiple cations and sintering temperature on microstructure and dielectric properties in Na1/2Ln1/2Cu3Ti4O12 (Ln = Sm and Eu) ceramic materials

“…Similarly, the mean grain size of NSCTO ceramics also increased with the increase of sintering temperature. The change in the grain size of the ceramics is usually associated with the liquid phase sintering mechanism, as reported in other CCTO-related ceramics 30 , 35 – 37 . However, in case of the NSCTO ceramics, the microstructure largely changed when the sintering temperature changed by only 25 °C.…”

“…ceramics. Samples Preparation method Sintering conditions Mean grain size (μm) Dielectric constant (1 kHz) Dielectric loss (1 kHz) References Bi 1/2 Na 1/2 Cu 3 Ti 4 O 12 Pechini method 1000 °C for 10 h 3.2 2.77 × 10 3 0.11 30 Na 1/2 Bi 1/2 Cu 3 Ti 4 O 12 Sol–gel 1000 °C for 3 h 2.2 ≈ 10 4 – 9 Na 1/3 Ca 1/3 Bi 1/3 Cu 3 Ti 4 O 12 Solid state method 1060 °C for 5 h 2–20 2.59 × 10 4 0.038 27 Na 1/2 Sm 1/2 Cu 3 Ti 4 O 12 Sol–gel 1050 °C for 18 h 3.67 8.04 × 10 3 0.045 31 Na 1/2 Sm 1/2 Cu 3 Ti 4 O 12 Solid state method 1110 °C for 10 h – 7.02 × 10 3 0.041 32 Na 1/2 La 1/2 Cu 3 Ti 4 O 12 Solid state method 1080 °C for 5 h 2–4 …”