PREPARATION AND CHARACTERIZATION OF NANOCRYSTALLINE Ba(Ti0.96SnxZr0.04-x)O3 CERAMIC
Nanocrystalline powders of Barium titanate (BaTiO3 or BT) and Ba(Ti0.96SnxZr0.04-x)O3 (BTSZ1, BTSZ2, and BTSZ3) [x=0.02, 0.03 and 0.04] have been synthesized by a combination of solid-state reaction and high energy ball- milling technique (HBM). The effect of increasing Sn content on the microstructure and dielectric properties of the ceramics were studied. X-ray diffraction patterns show cubic and tetragonal symmetry without secondary phase. Sn4+ and Zr4+ ions entered the perovskite-type cubic structure and led to an increase in the lattice parameters. The average crystallite size has been calculated using Scherrer formula. Using Scherrer, the crystallite size of the (110) peaks of the pure BT is 31.2 nm and that of BTSZ1, BTSZ2, and BTSZ3 are 42.7, 37.9 and 42.3 nm respectively. The FESEM results indicated a variation of grain size from 144.53, to 89.28 nm for the pure BT, BTSZ1, BTSZ2, and BTSZ3, which show a decrease in grain size as Sn doping increases. Frequency dependence of dielectric permittivity and loss studied in the range temperature and frequency range 30-400oC and 40 Hz–1 MHz, respectively, for BT, BTSZ1, BTSZ2, and BTSZ3 show a normal ferroelectric phase transition behavior. The corresponding dielectric constant and loss at room temperature show that BTSZ2 has the highest dielectric constant and loss of 1671 and 1.6 respectively. The high dielectric constants and relatively lower loss tangent values meet the current demand for device miniaturization in the electronics industry.