Synthesis, dielectric and nonlinear electrical properties of Na1/2Bi1/2Cu3Ti4O12 ceramics by a sol-gel technique

The Bi1/2Na1/2Cu3Ti4O12 (BNCTO) ceramics have been synthesized by a sol-gel technique, which were sintered at temperatures of 800 °C, 900 °C, 950 °C and 1000 °C for 3 hours. X-ray diffraction reveals that phase-pure BNCTO can be synthesized by this method with no impurity is found. It shows that, the dielectric and nonlinear electrical properties of the samples are strongly dependent on the sintering temperatures. With the sintering temperature increases, the dielectric constant value increases and the loss tangent decreases in the frequency range of 104-106 Hz. Similar to the CaCu3Ti4O12-based compound, the BNCTO ceramics also exhibit remarkably strong nonlinear current-voltage characteristic, and the nonlinear coefficient increases monotonically with the increase of sintering temperature.