Modification of structural and electrical properties of Ca element on barium titanate nano-material synthesized by hydrothermal method

ABSTRACT

Ba_1-xCa_xTiO₃ (x = 0.10, 0.15, 0.20 and 0.25) ceramics were prepared by using standard Sol-Gel hydrothermal reaction technique at 150°C. Structural and dielectric properties were carry out by using X-ray diffraction and dielectric constant, tangent loss and conductivity measurements. Single-phase perovskite-type X-ray diffraction patterns were observed and the samples have a phase with a tetrahedral structure at room temperature for all the compositions. SEM image of Ba_1-xCa _xTiO₃ powder shows inhomogeneity with the increment of Ca element. Small grains with average grain sizes of ∼20 ± 5 nm uniformly distributed over the mesocrystals. The temperature dependence of the dielectric permittivity of tetrahedral Ba_1-xCa_xTiO₃ ceramic as a function of frequency (1 kHz-100 kHz) at different temperature (RT–300°C) provided useful information on electrical behavior (Ferroelectric-Relaxor relationship). The behavior of the dielectric graph (in paraelectric region) confirmed the relaxor behavior of the material at high temperature (160–300°C) range. Nature of diffusivity graph also indicating that, increase of Ca content improved the diffusivity of materials. Values of T_m increased with increasing x = 0.10– 0.25, from ∼120°C to 140°C. In the comparison of other, the composition Ba_0.90Ca_0.10TiO₃ reveals strong results. It has dielectric permittivity (ϵ) 5741 ± 200 at the low value of loss tanδ = 0.009 ± .091 along with the transition temperature (T_c) at ∼131 ± 2 shows diffusivity 1.72 ± 10 < 2 and activation energy 0.821 ± .030.

KEYWORDS:

• BCT
• ferroelectric
• XRD
• SEM
• relative permittivity

Funding

Authors are grateful to the Defence Research and Development Organization (DRDO), Govt. of India, for financial support under the research project ERIP/ER/1303129/M/01/1564.